Wafer-based manufacturing of Micro-Optics is based on standard technologies from Semiconductor Industry, like resist coating, lithography, reactive ion etching, deposition, sputtering, and lift-off. These well-established technologies allow the manufacturing of almost any Micro-Optics' structure shape. The excellence of the Micro-Optics component depends much on the proper choice of the manufacturing equipment and the process control. As all processes are standard Semiconductor technology, the quality is merely a question of the budget and the optimization effort. For characterization and testing, the current situation is different. Neither the test equipment from Semiconductor industry nor the test equipment from classical optics manufacturing is suitable to for Micro-Optics. Most of test instruments Micro-Optics industry is using today have been developed by research institutes or by the manufacturing companies themselves. As Micro-Optics is still a niche market, all instruments are built in small series. This lack of suitable test equipment is a major problem for the Micro-Optics industry today. All process optimization in manufacturing is closely related to the capability to measure the quality of the products. We report on the state of the art in wafer-based manufacturing and summarize the standard characterization tools for Micro-Optics.

This paper will present recent developments in the field of microstructured plastic optics. Throughout the industry there is a steady push for improved precision and increased component efficiency as well as complexity. Discussed are different replication techniques and product enhancement capabilities, in particular coatings and nanostructures, such as top surface features of polymer optical components. Discussed are furthermore the properties, the efficiency, the application fields and the possible combinations of different AR-capabilities. We compare the periodical Motheye structure, the new random AR-structure PlasmAR (plasma based method) and the BBAR-coating (combination of chemical process and physical deposition process).

The uniform illumination of holographic screens during their recording process is commonly realized by using only the quasi-constant, inner part of the gaussian intensity profile of a very strongly expanded laser beam. This technique is characterized by a very low efficiency (about 5%, depending on the required uniformity). We present a method, which uses refractive, micro optical beamshaping elements in order to create a rectangular, extraordinarily uniform, flat-top intensity profile with minimal phase aberrations. This allows the use of about 80%-90% of the provided optical power for the illumination of the holographic screen. To ensure the required quality of the illumination wave, a spatial frequency filtering has to be applied. For certain holographic applications, requiring a combination of high beam-divergence and high optical power, conventional pinholes are either too thin or too sensitive. To solve this problem, we present a new concept of dielectric pinholes, based on optical microstructures. The combination of beamshaping elements and dielectric pinholes allowed us to extend the available parameter range during the recording of holograms.

We developed a fabrication process for microoptical elements with continuous profiles. In contrast to gray tone lithography with the cost intensive HEBS-glass or direct writing by laser or electron beam and the closely connected expensive equipment, the presented technique allows a low budget fabrication of continuous profiles with smooth surfaces. We use conventional binary photolithography with standard DNQ-Novolak based photoresist, simple smoothing techniques and proportional transfer by dry etching. All variations of the procedure are based on the local depth control with the local filling factor of a periodic pattern in a binary photomask. The filling factor of the mask defines the resist volume, which corresponds to an effective layer thickness. With the aid of smoothing techniques after development, the effective resist layer thickness is transformed to the real local profile thickness. Thus, continuous change of the filling factor in the periodic mask pattern results in a smooth height profile. Furthermore, it is possible to fabricate continuous height profiles with just one lithographic step if the mask pattern can not be resolved by the exposure-system. This can be achieved by the use of smaller periods or by increasing the gap between mask and substrate. The need of further surface smoothing depends on the smoothness demands. With the help of continuous resist profiles, fabricated by smoothing of binary resist patterns and also by using non-resolvable masks, combined with further binary structuring after the proportional transfer, three dimensional waveguide taper for low loss fiber-waveguide coupling via mode matching were successfully manufactured.

We present a technique for the fabrication of small period structures using a near field holography setup. Using a two-dimensionally structured phase mask, the creation of two-dimensional hole or dot arrays was possible with one single exposure step. In order to get a high contrast interference pattern, the mask parameters were optimized by rigorous calculation to achieve equal transmission efficiency in the respective diffraction orders. The mask generation was done by electron beam lithography and ion beam etching. We have made exposures with two different setups. The first setup is an exposure with normal incidence, where the interference of the four first diffraction orders is used. The second setup uses the zeroth and first diffraction order interference of a conical incident beam.

Experimental and calculated characterization of resonance domain surface relief gratings with different groove shapes, groove depths, and groove slant angles are presented. Our results reveal that Bragg type diffraction, with efficiencies of about 90% can be achieved by properly choosing certain parameters of the resonance domain surface relief gratings.

One of the actual challenges in optics is the fabrication of micro lenses as a part of MEMS or even integrated in macroscopic systems. This task needs a completely new category of metrology devices. To fill the gap in dimensions occuring with this technologies between the milli-/micrometer technology and the nano-/subnanometer technology, it is now possible for the surface measuring instrument MicroGlider^(R) from FRT GmbH to be optionally equipped with up to 17 different sensors, most of which are optical sensors. Various optical principles are under use, to meet the different needs of devices under investigation, depending on material, surface character or necessary resolution. In addition an Atomic Force Microscope (AFM) may also be added. The AFM is fixed to the instrument additionally to the standard optical topography sensor. If necessary, a spot will be selected into the available overview measurement to determine the measuring range of the AFM. The AFM is able to investigate structures down to the atomic range. The measuring instrument enables the combination of measuring ranges from 100 mm, 350 mm or 600 mm with resolutions down to the sub-nanometer range in one single instrument.

We present an innovative method Optical Diffraction Microscopy (ODM). for the simultaneous measurement of specular and non-specular diffraction patterns of sub-micron periodic structures. A sample is illuminated with broadband light and the diffraction pattern is collected by using a pair of ellipsoidal mirrors, optical fibers and a spectrometer. This method allows for rapid measurements and makes used of the Rigorous Coupled Wave algorithm for data analysis. In the present work the method has been applied to binary and multi-layer sub-micron gratings. A series of binary gratings with periods of 318 nm and 360 nm with different exposure levels of the photoresist were investigated. We succeded in characterize underexposed, ideally exposed and overexposed photoresist grating profiles. The measurements are well-suited to determine the delivered exposure energy density to photoresist gratings. The ODM technique may thus be applied to specify the exposure window and as a feedback in order to adjust the exposure energy density on-line. The homogeneity of a grating on multi-layered substrate has been investigated. Heights and duty cycles ranging from 50 nm to 55 nm and 0.25 to 0.97, respectively, have been found. AFM measurements of the gratings verify the ODM results and demonstrate that the ODM technique can be used to determine grating topology.

Driven by increasing precision and accuracy requirements due to miniaturization and performance enhancement, measuring technologies need alternative ways of positioning, probing and measurement strategies. The paper describes the operation of the high-precision wide scale three-dimensional nanopositioning and nanomeasuring machine (NPM-Machine) having a resolution of 0.1 nm over the positioning and measuring range of 25 mm x 25 mm x 5 mm. The NPM-Machine has been developed by the Technische Universitat Ilmenau and manufactured by the SIOS Messtechnik GmbH Ilmenau. Three plane-mirror miniature interferometers and two angular sensors are arranged, to realize in all three coordinates zero Abbe offset measurements. Therefore, this device closes a gap in coordinate-measuring technique regarding resolution, accuracy and measuring range. The machines are operating successfully in several German and foreign research institutes including the Physikalisch-Technische Bundesanstalt (PTB). The integration of several, optical and tactile probe systems and scanning force microscopes makes the NPM-Machine suitable for various tasks, such as large-area scanning probe microscopy, mask and water inspection, circuit testing as well as measuring optical and mechanical precision work pieces such as micro lens arrays, concave lenses, step height standards.

Surface structures with lateral dimensions in the nanometer range (⪅ 100 nm) have a significant impact on the optical and functional surface properties. Scanning Force Microscopy (SFM) has been increasingly used to investigate the nanotopography of substrates and thin films. SFM data evaluation is nevertheless so far mainly restricted to qualitative image information or single roughness parameters. Appropriate description of statistical surface roughness needs an advanced quantitative data analysis, which can be accomplished by Power Spectral Density (PSD) functions. For nanostructures conclusions about the information content of measurement results are difficult and only possible in a qualified manner. The results can be strongly influenced by the geometry of the probe tip, whose lateral dimension is in the nanometer range too. Based on experimental/empirical work, we estimated tip size effects on the PSDs of thin films. Especially the SFM measurement of super smooth samples (e.g. substrates for EUV coatings) can also be affected by inherent noise of the system. We therefore also present and discuss methods of noise analysis.

Subaperture polishing technologies have radically changed the landscape of precision optics manufacturing and enabled the production of higher precision optics with increasingly difficult figure requirements. However, metrology is a critical piece of the optics fabrication process, and the dependence on interferometry is especially acute for computer-controlled, deterministic finishing. Without accurate full-aperture metrology, figure correction using subaperture polishing technologies would not be possible. QED Technologies has developed the Subaperture Stitching Interferometer (SSI) that extends the effective aperture and dynamic range of a phase measuring interferometer. The SSI's novel developments in software and hardware improve the capacity and accuracy of traditional interferometers, overcoming many of the limitations previously faced. The SSI performs high-accuracy automated measurements of spheres, flats, and mild aspheres up to 200 mm in diameter by stitching subaperture data. The system combines a six-axis precision workstation, a commercial Fizeau interferometer of 4" or 6" aperture, and dedicated software. QED's software automates the measurement design, data acquisition, and mathematical reconstruction of the full-aperture phase map. The stitching algorithm incorporates a general framework for compensating several types of errors introduced by the interferometer and stage mechanics. These include positioning errors, viewing system distortion, the system reference wave error, etc. The SSI has been proven to deliver the accurate and flexible metrology that is vital to precision optics fabrication. This paper will briefly review the capabilities of the SSI as a production-ready, metrology system that enables costeffective manufacturing of precision optical surfaces.

The continuing miniaturization in many technologies - among them the optical systems - demands high-resolution measurements with uncertainties in the nanometre-range or even well below. A brief introduction of measurement methods used at the micro- & nanometre scale is therefore given as introduction. While a wide range of these methods are well established for the determination of various physical properties down to the nanometric scale, it is Scanning Probe Microscopy (SPM) that provides a unique direct access to topographic surface features in the size range from atomic diameters to some ten or hundred micrometres. With the increasing use of SPMs as quantitative measurement instruments, the demand for standardized calibration routines also for this type of instruments rises. However, except for a few specially designed set-ups mainly at National Metrology Institutes (e. g. PTB in Germany), measurements made with SPMs usually lack traceability to the metre definition. A number of physical transfer standards have therefore been developed and are already available commercially. While detailed knowledge of the standards' properties is a prerequisite for their practical applicability, the calibration procedure itself deserves careful consideration as well. As there is, up to now, no generally accepted concept how to perform SPM calibrations, guidelines are now being developed on various national and international levels, e. g. VDI/VDE-GMA in Germany and ISO. This papers discusses the draft of an SPM calibration guideline by focusing on several critical practical aspects of SPM calibration. The paper intends to invite the readers to take active part in guideline discussions.

Although the measurement of the laser-induced damage threshold is a field of permanent research effort since the late 1960s, the optimization of the damage handling capability is still a key issue for the development of high performance laser systems. In conjunction with the ever increasing demand for lasers with high average power, energy, extreme wavelengths or short pulses, the resistance to laser damage has to be optimized with a special regard to the different damage mechanisms. Therefore, a report of the current status of the laser-induced damage threshold is given for the most interesting components and laser systems applied in science and industry. Further, several results of recently performed damage investigations in the NIR spectral range and for ultra short pulses are presented in this paper. The reliability of damage threshold measurements is crucially depending on the chosen test parameters. The importance of the different parameter values were investigated carefully during several Round-Robin experiments. These investigations can be regarded as the basis of the standardization process leading to the International Standard ISO 11254. In this paper, selected results of the comparative campaigns in damage testing are described, especially in the field of ns and fs pulses.

Atomic force microscopy (AFM) has proven to be a powerful tool to observe topographical details at the nano- and subnanometer scale. Since this is a rather new technique, new enhancements with faster scanning rates, more accurate measurements and more detailed information were developed. This requires also a higher demand on the signal processing and the controlling software. Operating an AFM with analog driven hardware is often limited by drift and noise problems. Here we overcome this problem by introducing digital signal processing capable of accurately stabilizing the piezo control in the newly developed TREC (topography and recognition imaging) mode. In this mode topographical information and molecular recognition between tip bound ligand and surface bound receptors is simultaneously acquired. The sought information is conveyed by slight variations of the minima and maxima of the signal amplitudes. These variations are very small compared to the maximum possible DC deflection. Furthermore, the DC offset exhibits a rather large drift mostly attributed to temperature changes. To obtain reliable tracking results the oscillating photodiode signal needs to be nonlinearly filtered and efficiently separated into four major components: the maxima, the minima, the spatial average of the maxima, and the spatial average of the minima. The recognition image is then obtained by a nonlinear combination of these four components evaluated at spatial locations derived from the zero-crossings of the differentiated signal resulting from a modified differentiator FIR filter. Furthermore, to reliably estimate the DC drift an exponential tracking of the extrema by a first-order IIR filter is performed. The applicability of the proposed algorithms is demonstrated for biotin and avidin.

The successful realization of devices based on two-dimensional (2D) photonic crystal structures relies on an accurate characterization of the properties of the fabricated nanostructured surface. Scanning electron microscope (SEM) images allow the verification of geometric parameters of fabricated 2D-photonic crystal structures such as the periodicity or the hole diameter. In order to investigate the optical properties of 2D-photonic crystals we realized an experimental setup for spectrally and spatially resolved transmission measurements at normal incidence. These measurements reveal the allowed modes of the photonic crystal at the Gamma-point. In contrast to transmission measurements in the plane of the photonic crystal, these measurements are independent of the lateral termination of the structure, since only the area of the photonic crystal is probed. The experimental setup allows for the characterization of microscopic structures of dimensions down to 50 micrometers in diameter. The setup can furthermore be utilized to characterize the spatial homogeneity of larger nanostructured surfaces. We present experimental results and compare them to photonic band structure calculations.

A characterization of optical surface properties, especially in terms of the human visual perception, demands the use of BRDF data over a wide spectral range, at least over VIS. Further it could be interesting to perform a fast optical material recognition in industrial metrology. For the fast acquisition of large amounts of BRDF data over wavelength a small, fast and rugged spectro-radiometer without moving parts for angular resolution was developed. The semi- hemispherical measurement system is derived from a full-hemispherical set-up. It consists of a catadioptric system with an elliptical mirror mapping a semi-hemisphere onto a commercially available cartesian CMOS sensor with a dynamic range of 112dB. The sensor consists of 322096 pixels, producing an equivalent angle resolution. The system can take up to 53 semi-hemispherical BRDFs per second. The incoherent illumination is provided by a set of assorted LEDs. A radiometric measurement is possible over a wide spectral range from VIS to NIR over approximately 6.5 decades. Fast property characterization and material recognition from multivariate data in industrial applications demand appropriate analysis methods. As an analysis method a linear canonical discriminant analysis is applied to the data over angles and wavelength. In the paper measurement analysis results of the spectral signatures of various materials and test surfaces will be presented. Classification results and performances will be compared and discussed.

There is significant sophistication in the individual fields of fabrication, coating, and metrology. Uncoated optics are characterized accurately by a wide array of techniques, as are optical coatings. However, often the coating process can change the intrinsic properties of the polished substrate such as figure, microroughness, defect density and so scattering properties. Optical components can often be distorted out of specification during assembly by contacting or cementing, and during mounting. This presentation will give examples of the interplay of all processes from fabrication, cleaning, coating, assembling and mounting on the measured performance of some precision optical components and assemblies.

ASPHERO5 is a funded research project (project prime: Schneider OpticalMachines) with the goal of economic fabrication of high precision aspheres. The research is concentrated on the classical process chain consisting of grinding and polishing. The mid spatial artefacts are one of the limiting factors for grinding, whereas for polishing the variation of the local removal rate depends on the local curvature. In this paper first results of minimizing mid spatial artefacts for the grinding step and analyzing local removal rates for the polishing step are reported. Based on the results of our research, aspheres with local radii from 200 mm to 10 mm are polished to 25 nm rms final surface error. Nevertheless, to perform the different process steps in an economic way is still a challenge.

MUSE (Multi Unit Spectroscopic Explorer) is a second generation integral field spectrograph proposed to the European Southern Observatory (ESO) for the VLT. MUSE combines a 1' x 1' Field of View (FoV) with a spectral resolution going to 3000 and a spatial resolution of 0.2" provided by the GALACSI adaptive optics system. MUSE is operating in the visible and near IR wavelength range (0.465-0.93 μm). It is composed of 24 identical integral field units; each one incorporates an advanced image slicer made of a combination of mirrors and mini-lenses arrays. During the feasibility study, a slicer prototype has been designed, manufactured and tested. This paper firstly describes an original approach for the slicer optical design and manufacturing. Then, we will focus on the optical tests of the prototype. These tests included the control of the angular tilts and assembling method of the slicer, the measurements of the position, size and shape of the pseudo-slits, the measurements of the Point Spread Function (PSF) for the slice-slit imagery on the whole FoV and an estimation of the size of the global exit pupil. We finally conclude on the feasibility of MUSE image slicer and its possible improvement for the next design phase.

Computer generated holograms (CGH) are widely used in combination with standard Fizeau interferometers. The test of plane and spherical specimen is extended to the test of aspherical surfaces. The wave from a transmission flat or a transmission sphere is formed by the CGH to fit the surface of an asphere or a cylinder. There are some considerations for an advantageous design of this additional optical element in the beam path. The availability of a suitably designed CGH is often the limitation for the manufacturing of precision aspheres. JENOPTIK Laser, Optik, Systeme GmbH can provide a custom made CGH within a short time. We will show the design principles and the layout of the CGHs. The optical properties and the known limitations will be presented based on measurements of aspherical surfaces.

Subaperture polishing technologies have radically changed the landscape of precision optics manufacturing and enabled the production of components with higher accuracies and increasingly difficult figure requirements. Magnetorheological Finishing (MRF), for example, is a production-proven, deterministic, subaperture finishing technology that has excelled at overcoming the limitations of traditional polishing. Several recent MRF developments will be presented, including complementing Single Point Diamond Turning (SPDT) technology, transmitted wavefront correction, and finishing of increasingly large apertures. We will also discuss the high precision finishing of challenging optics using a newly developed jet-based technology. A series of examples spanning a wide range of materials, geometries and specifications will be presented. Specific areas to be discussed include micro-optics (i.e., optics less than 5 mm in size), which typically require a very labor-intensive iterative process to finish, and steeply concave optics, such as domes, which are typically not well suited for sub-aperture polishing processes.

The fabrication of diamond-based optical elements for high-power CO₂ lasers is of particular interest because of the low optical absorption coefficient of this material in combination with it's very high thermal conductivity and the weak temperature dependence of refractive index¹. Recent advances in gas-phase synthesis have made it possible to fabricate polycrystalline CVD diamond films (DF) whose optical and thermal properties are close to those of single crystal diamond material, whereas they are far cheaper. As a result, these sophisticated materials are applied more and more to tasks dominated till now by other materials. Such examples for this are windows for high-power CO₂ lasers in the 5 - 20 kW domain¹ and beam-splitters². Recently new techniques have been proposed for antireflective structuring of DF surface^3,4 as well as for generation of phase microrelief to manufacture diamond diffractive optical elements (DOEs) for the far IR range^5-8. The realisation of DOE by UV-laser ablation has been considered^5-8. Using of ion-chemical etching and plasmochemical-etching⁹ is considered later¹⁰. The present paper is devoted to further development of considered approaches^5,9. The realization of diamond diffractive optical elements (DOEs) is considered, able to focus an incoming CO₂ laser beam into certain pregiven focal domains. Results of experimental investigation of designed DOEs are presented and discussed.

The Megajoule laser, designed for the study of high energy density plasma, is currently being constructed at the CEA Cesta near Bordeaux in France. Constituted of 240 laser beams, this facility will by able to concentrate 1.8MJ of energy on a target placed in the centre of a vacuum chamber in order to obtain fusion. The 240 beams of the LMJ have a right section of 40 x 40 cm² and are equipped with about 40 optical parts of various types: laser slabs, lenses, mirrors, diffractive optics. All of them have to sustain very high fluence induced by the laser beam. Manufacturing 9000 large laser optics of this type is a real technological and economical challenge. This presentation gives an overview of this activity and details the main recent development realized. In addition, we present results on the current development program made to improve lifetime of fused silica optics at the wavelength of 351 nm.

At Sagem-REOSC we are in the last phase of figuring of the Gran Telescopio Canarias Primary Mirror Segments and Secondary Mirror. This paper's intent is to show, from the optical manufacturer point of view, how astronomy is presently evolving from large monolithic Active Mirrors to segmented optics thus raising new manufacturing challenges. For this we will recall the work done during VLT & Gemini, gaive latest status on Gran Telescopio Canarias and make a rapid overview of the on-going Extremely Large Telescope projects with primary mirror diameter above 20-m.

Many hundreds of mirror segments of 1-2 metre size will be needed to realise the next generation ground based extra large telescopes (ELTs). This paper introduces the design of a new ultra precise large optics grinding machine; Big OptiX or simply 'BOX^TM'. This machine has been conceived to have unprecedented dynamic loop stiffness enabling ultra precise large 'free-form' optics to be rapidly ground within a serial production environment. Form accuracy capability of this machine will be 1 um per metre aperture and low levels of induced sub-surface damage will minimise the processing time of subsequent 'polishing' processes.

The recent upsurge in the demand for off-axis and complex "freeform" optical surfaces is driving the development of novel processes for their fabrication. This paper focuses on recent developments of the Precessions CNC polishing process for freeform surfaces, including off-axis as a special case. First, the surface-prescription and metrology-data, and their relation to the data-input for the polishing machines, are considered. The relevance of consistent coordinate frames is emphasised. An outline of how the process can 'polish' a ground freeform part (improve the texture), and then 'figure' the part (reduce the form errors) is given. Specific experimental case-studies are then presented, illustrating the versatility of the process on different materials and forms. Recent work is included in which the process-speed has been moderated in order to remove tens of nanometres of stock material, rather then the more usual hundreds of nanometres to tens of microns as in the standard Precessions process. The relevance of this to improving the ultimate surface-precision that should be achievable by this method is described. As a final illustration, the potential of the process to the rapid fabrication of the hundreds to thousands of 1-2 metre class mirror segments required for extremely large telescopes is considered.

Off-axis paraboloids provide sophisticated challenges in both machining and measuring. There are 2 accepted approaches for manufacturing off-axis paraboloids. In method one, a rotationally symmetrical part is shaped and polished with subsequent separating the off-axis elements from the block. On the other hand, one can machine the single parts right from the start. In this case the surface is kind of free-form. In this paper we report on the manufacturing of mirrors for both methods. Special attention is paid to machining and measuring. The fabrication process consists of iteration steps. The polishing step can remove the remaining shape error of the mirror surface itself or the wave front of the system.

Ongoing laser fusion experiments like the "Laser MegaJoule Project" and the "National Ignition Facility" have created a strong demand for large optical lenses of special grade fused silica. The required lens dimension poses several challenges to the manufacturing process. One of the key issues is to provide a suitable measurement technique, which is capable to fulfill the extreme demands for characterizing the optical homogeneity of those large fused silica blanks. We report on our first results achieved with an interferometer system that was installed to explore the potential and feasibility of stitching interferometry. Although the principle of stitching is well known, it had to be adapted to the special "oil-on measurement technique" that is necessary to characterize lens blanks without expensive surface polishing.

The next generation of infrared - sub mm space telescopes requires reflectors with large dimensions, high quality and, according to weight issues, are based on composite or new materials technology. The challenging tasks of on-ground testing are to achieve the required accuracy in the measurement of these reflectors shape and antenna structures and to verify their performance under simulated space conditions (vacuum, low-high temperatures). A holographic camera for the verification and validation of this type of reflector in a space environment is presented. A diffuser is implemented to measure the deformations of reflective surfaces in a more flexible way. The system has been made compatible with the vacuum conditions. Some elements of the holographic camera (camera lenses, CCD, crystal, optical fibre) have been adapted and tested under vacuum. The metrological certification of the whole system is realised by the measurement of a parabolic CFRP reflector with a 1.1 meter diameter. The results are compared to the one achieved with a high spatial resolution IR interferometer on the same reflector in laboratory conditions and under thermal vacuum conditions. This later test consists in measuring the deformations of the reflector between an initial state at a selected temperature and a final state at another temperature. The comparison between the high spatial resolution IR interferometer and this dynamic holographic method showed very good qualitative and quantitative agreement between the techniques, thus verifying the potential of this new Holographic approach.

In this paper, we describe our recent activities on wave-front measurement of space infrared telescopes. Optical performance of the 685-mm lightweight telescope on board the Japanese infrared astronomical satellite, ASTRO-F, has been evaluated at cryogenic temperatures. The mirrors of the ASTRO-F telescope are made of sandwich-type silicon carbide (SiC) material, comprising porous core and CVD coat of SiC on the surface. The total wavefront errors of the telescope were measured with an interferometer from outside a liquid-helium chamber; a 75-cm reflecting flat mirror was used for auto-collimating the light from the interferometer. The cryogenic deformation of the flat mirror was derived independently by shifting it in the chamber and its contribution to the wavefront error was removed. In addition to the ASTRO-F telescope, we are currently developing a 3.5-m telescope system for SPICA, the next Japanese infrared astronomical satellite project. Details of our methodology for the ASTRO-F telescope, together with our optical test plan for the SPICA telescope, are reported.

Shearing interferometry is a well-established technique for high accuracy optical testing. During evaluation usually piston and tilt in the wavefront are neglected because the interest is in higher order surface or wavefront aberrations. Looking for absolute testing of elements or systems and similar tasks, the evaluation of the tilt in the wavefront between measurements is important too. Several types of shearing ineterferometers are in use. The paper discusses briefly tilt measurement in rotational- and radial- shearing interferometers, but further details lateral shearing interferometers. In lateral shearing interferometry only a difference of the wavefront sheared with itself is measured and therefore wavefront tilt does not show up as fringes, only as a bias to the fringe position. The problems associated with measuring tilt accurately using the standard lateral shearing configuration are discussed and a technique using a variable shear, which allows making wavefront tilt visible to the operator in form of fringes is described. Several solutions to implement this variable shear approach are presented. In all types of shearing interferometer a close look has to be kept at the spatial coherence of the wavefront under test. In general the spatial coherence has to be large enough yield good fringe contrast for the desired shear. In UV applications Excimer-lasers don't have high spatial coherence and high spatial coherence is not desired anyway to reduce coherent noise in the system. Relating to this we discuss solutions for dealing with low spatial coherent light for the variable shear technique. Measurement examples of tilt using variable shear with lateral shearing interferometry and a comparison to a Twyman-Green interferometer in the UV region are presented as well.

Least square (LS) methods are an alternate approach to phase shifting interferometry algorithms for object shape measurement in the presence of unequal phase steps. One of the sources of unequal steps is vibrations. We study the influence of vibrations on intensity data and compare the obtained results with a LS and classic PSI algorithms. We find that in the case when no vibrations are present, both methods give similar results, while when vibrations are present LS methods generated slightly better results than the PSI algorithm. The results for both methods worsen significantly as the amplitude of the vibrations increases. We also show that a different set of phase steps than those found by LS method, while not generating minimal error function, can yield a better phase result with no residual phase error.

This paper presents a fibre-based low coherence interferometric sensor developed by FOGALE nanotech. Based on the proven principle of partial coherence interferometry the sensor works as a comparator of optical path lengths. The optical path lengths along the optical axis in the measurement interferometer arm containing a target object are compared with the optical path lengths in an internal delay line. Multiple, partially reflecting surfaces of the target can be detected during one scan of the delay line. Standard measurement ranges are between a few mm up to 400 mm (optical thickness). Longer measurement ranges are available on request. The measurement zone can be placed at a distance of up to several meters away from the instrument's exit. The sensor reaches an absolute accuracy on position measurements down to ±100 nm over the full measurement range. The system has been successfully applied in industry (glass and optical) as well as in research environments, e.g. for the dimensional metrology of large astronomical telescopes. This paper focuses on an innovative application of the sensor in the optics manufacturing industry. The paper starts with a description of the measurement technique, the system hardware concept, the detection and signal processing scheme. We present a modeling-based approach for the dimensional metrology of optical components (e.g. single lenses, windows, prisms) or complete, mounted systems where the positions of all individual elements can be detected. A comprehensive propagation model including dispersion and phase effects is used to extract the distances from the optical path differences. Prior to a measurement, the optimum tailoring of the measurement beam is obtained by a simulation of the beam propagation through the target object. This ensures that each surface to be measured delivers a sufficiently strong signal. To illustrate our approach we present its application in the fabrication process of complex optical systems where "global" metrology of complete systems can be performed with a very high accuracy in a short time.

Based on lateral shearing interferometry, a powerful technique, called the Quadri-Wave Lateral Shearing Interferometer (QWLSI), is used to evaluate the wave-front distortions with a high accuracy. Our device can be used for the characterization of complex and very aberrant optical devices, the testing of optical components, the control of adaptive optics and also for laser beam evaluation. The particular design of the QWLSI provides him interesting properties for wave-front metrology such as a high transverse resolution, a tunable sensitivity or also an evaluation of the measurement error. An innovative interferogram analysis allows also an increasing accuracy of the measurement. After dealing with these aspects, we will conclude by presenting an experimental wave-front analysis of a femtosecond laser pulse and an analysis in the far infrared spectral range [λ=8-14 μm].

The use of Wavefront Sensors (WFS) is nowadays essential in the field of instrumental optics. In this communication, I present and discuss the principle of a new, recently proposed family of WFS. Their principle consists in evaluating the slopes of the Wavefront Errors (WFE) by means of varying density filters placed into the image plane of the tested optical system (the device is sometimes called "optical differentiation WFS"). The wavefronts are reconstructed from the obtained slopes digitally. Various luminous sources of different wavelengths, spectral widths and spatial sizes can be employed. The capacities of the method are discussed from the geometrical and Fourier optics points of view, then illustrated by a few numerical simulations showing some examples of practical applications. Two different measurement configurations are also schematically described and commented.

Interferometric asphere testing is traditionally done using computer generated holograms (CGHs) as beam shaping optics. The great disadvantage of using CGHs is that each asphere requires its own unique CGH which is expensive and requires a certain delivery time. In many cases all you are interested in first off is a quick but rough sample conformity validation to investigate and test new asphere designs. We present a new method which allows you to test rotational-symmetrical aspheres interferometrically in a spherical or plano setup. This means without expensive auxiliary beam shaping optics. The systematic setup error is automatically removed from the measurement results, so that the displayed results correspond with the traditionally known interferometer results with adapted wave fronts. Based on this method a modification of this basic method is presented that allows you to control the manufacturing process.

The measurement of aberrations is essential to qualify and improve optical system performance. Interferometry and Shack-Hartmann test are well known methods, which usually characterize only a component of the system. In addition the field dependence of aberrations is difficult to determine with these methods. We evaluated the iterative approach based on Gerchberg Saxton Algorithm and optimized its accuracy for experimental data. The aberrations are determined from image stacks formed by a point source with varying focus position. In addition to calculating the aberrations also apodisation can be taken into account. The numerical accuracy of the technique is up to 1/100 of a wavelength (Fringe Zernike coefficients) for ideal noiseless detection. For experimental data the main uncertainty is caused by model assumptions as the precise numerical aperture, deconvolution for finite pinhole sizes, magnification or step size in defocus as well as accuracy of equipment. The dismatch between retrieval and direct wavefront measurement is less than 1/20 of a wavelength. Additionally the influence of different components of the optical system may be separated by measurements with exchanged components. The adjustment of an objective lens was tracked with respect to the movement of the lens elements.

Wavefront sensors, particularly those of the Hartmann-Shack type are now available in commercial form from several manufacturers. They have found increasing use in medical and industrial applications and, for consistent measurements over a range of instruments and measurement situations, traceability of measurement is essential. We have investigated the use of simple artefacts such as an optical plate and a plano-convex lens, used with a point source, to generate prescribed values of optical aberration. Measured values obtained with Hartmann-Shack sensors are verified by comparison with calculated results and measurement by other means.

Our work presents a method for evaluation of very small phase variations that uses the interference of polychromatic light using the principle of polarization interferometry. The phase change affects the color of the interference pattern, and color of the interference pattern corresponds to a specific phase change that can be evaluated using colorimetric techniques. We describe and analyse the colorimetric method for phase evaluation in our work. The proposed method offers accurate results and it is suitable for practical utilization in optical testing techniques.

Depending on the application, different characterization techniques are appropriate for bare and thin-film-coated optics. It is essential that substrates to be coated with thin films be dust free and do not contain surface films that interfere with the adhesion of the coatings. All surfaces must be inspected before making any measurements or before attempting to clean them. The cleaning technique used for a dirty surface will depend on its intended use and the type of contamination that is present. Some coated surfaces cannot be cleaned. Surfaces should also always be inspected after they are cleaned. Meaningful surface topography information can only be obtained on surfaces that have true surface structure from the fabrication and coating processes without additional contamination.

In further development of an existing semi-hemispherical spectro-radiometer without moving parts for angular resolution based on an elliptical mirror, a full-hemispherical device was designed. For the purpose of cost reduction and reproducibility it was decided to switch from the formerly used log-polar sensor to a commercially available cartesian CMOS camera with a dynamic range of 112dB. The sensor consists of 322096 pixels, producing an equivalent angle resolution. The system can take up to 53 full-hemispherical BRDFs per second. Illumination is provided by a set of assorted LEDs. A radiometric measurement over a wide spectral range from VIS to NIR requires a pixelwise calibration taking into account the spectral characteristics of the light source, filters, elliptical mirror and the CMOS-detector itself. However, the most important problems during calibration are the spectral response of the CMOS-detector, as well as its sensitivity as a function of the angle of the incident light. Also the elliptical mirror has a reflectivity which is a function of the incident angle, the wavelength and polarization of the collected light. All these influences have to be taken into account, if a proper radiometric measurement shall be conducted. The paper deals with the instrument design, the calibration procedures and gives some measurement results.

For precise angle resolved scatter (ARS) investigations on optical components, a scatterometer has been developed, which allows three dimensional scanning of the scattered radiation from the test specimen. By combining the set-up with different radiation sources, measurements in the spectral region from the DUV- to the NIR-spectral range can be performed. The optical properties of the components: reflection, transmittance, and the scatter behavior can be determined in the same run. The measured data are absolutely calibrated to the incident power. In this paper, we report about ARS- measurements on different samples such as holographic gratings, bare and anti reflective coated substrates. Additionally, results of scatter measurements on high reflective mirrors for 633nm with different numbers of layers will be presented. The comparison of the ARS-data and the results of Total Scattering (according to ISO 13696) on the same samples will be discussed.

Driven by the increasing requirements for optical surfaces, components, and systems, scattering techniques for the analysis of optical losses, roughness and defects face novel challenges for high sensitivity and flexibility. In this paper we present set-ups developed at the Fraunhofer Institute in Jena for total scattering (TS) and angle resolved scattering (ARS) measurements from the vacuum ultraviolet (VUV) and deep ultraviolet (DUV) over the visible (VIS) up to the infrared (IR) spectral regions. Extremely high sensitivities down to 0.05 ppm have been achieved for TS measurements and a dynamic range of up to 15 orders of magnitude for ARS. The performance is demonstrated by examples for roughness analysis of smooth surfaces and scatter analysis of multilayer coatings and diamond-turned mirrors.

The validity of the Ellipsometry of Angular Resolved Scattering technique introduced in a well known scatterometer has been demonstrated. The results were applied to the separation of surface and bulk effects in low-loss samples, because first-order scattering only depends on the origin of scattering, not on the topography or microstructure. The major point that we address is then the generalization of the separation technique (surface or bulk) to arbitrary heterogeneous samples with high level diffuse reflectance. The problem is strongly different since phase data from these samples depend on microstructure, not only on the physical origin of scattering.

A network for prototyping imaging lenses using injection moulding was established in Finland. The network consists of several academic and industrial partners capable of designing, processing and characterising imaging lenses produced by injection moulding technology. In order to validate the operation of the network a demonstrator lens was produced. The process steps included in the manufacturing were lens specification, designing and modelling, material selection, mould tooling, moulding process simulation, injection moulding and characterisation. A magnifying imaging singlet lens to be used as an add-on in a camera phone was selected as a demonstrator. The design of the add-on lens proved to be somewhat challenging, but a double aspheric singlet lens design fulfilling nearly the requirement specification was produced. In the material selection task the overall characteristics profile of polymethyl methacrylate (PMMA) material was seen to be the most fitting to the pilot case. It is a low cost material with good moulding properties and therefore it was selected as a material for the pilot lens. Lens mould design was performed using I-DEAS and tested by using MoldFlow 3D injection moulding simulation software. The simulations predicted the achievable lens quality in the processing, when using a two-cavity mould design. First cavity was tooled directly into the mould plate and the second cavity was made by tooling separate insert pieces for the mould. Mould material was steel and the inserts were made from Moldmax copper alloy. Parts were tooled with high speed milling machines. Insert pieces were hand polished after tooling. Prototype lenses were injection moulded using two PMMA grades, namely 6N and 7N. Different process parameters were also experimented in the injection moulding test runs. Prototypes were characterised by measuring mechanical dimensions, surface profile, roughness and MTF of the lenses. Characterisations showed that the lens surface RMS roughness was 30-50 nm and the profile deviation was 5 μm from the design at a distance of 0.3 mm from the lens vertex. These manufacturing defects caused that the measured MTF values were lower than designed. The lens overall quality, however, was adequate to demonstrate the concept successfully. Through the implementation of the demonstrator lens we could test effectively different stages of the manufacturing process and get information about process component weight and risk factors and validate the overall performance of the network.

This paper is intended to analyze the relative merits of low CTE glass, SiC and Beryllium as candidates for lightweight mirror substrates in connection with real practical experience and example or three major projects using these three materials and running presently at SAGEM-REOSC. Beryllium and SiC have nice thermal and mechanical properties but machined glass ceramic can still well compete technically or economically in some cases.

There are well known methods and equipments for measuring the specular (/directed) reflectance of a sample. There are quite different sample types such as laser mirrors or anti-reflectance material. Most of the common set-ups are not very flexible (e.g. only one angle ore only one wavelength), critical in accuracy, extremely expensive ore difficult to use. A new development from PerkinElmer tries to combine: high flexibility, high precision, easy to use, comparably low cost. The system is able to measure all type of samples from high reflectance to anti reflective coatings. It covers a large wavelength range of 185...3100 nm and is able to measure fully automated a couple of self-defined angles (8...68°) in S and P polarisation with only one interaction at the beginning (pressing the start button). No alignment is necessary in the daily use. The system works with an absolute measurement mode and therefore does not need any calibrated standard mirrors. The intent of this contribution is to introduce this new technology in comparison to traditional measurements.

Cemented doublets and triplets can not be used for objectives working at wavelengths of 248 nm and shorter, because the optical cement can not withstand the high photon energies. It will be shown that high NA deep UV objectives can be designed and built successfully with the help of air spaced doublets. Assuring Strehl ratios above 95% enforces very tight tolerances. For example the distance error of the lens vertex to its mount has to be less than 1 μm. This calls for a new manufacturing precision never realized before in series production. We show how a white light Mirau interferometer can be used to measure lens vertex positions with an accuracy of 200 nm. We also demonstrate how the fine-tuning process can be optimized by using a "simulated star test", where the point-spread function is calculated in real time with a FFT-algorithm from the optical path difference data, acquired by a Twyman-Green interferometer. To realize the required precision, today various measurement techniques and production processes are used. Picking up the subgroups on different machining tools and measurement systems will loosen the accuracy. Here, we present the concept and the layout of a new manufacturing tool where we implemented the different measurement techniques needed in one CNC machining center. This tool is able to 1) adjust automatically the optical axis of the subgroups related to the machining axis better than 0.5 μm with the help of the stick-slip effect where a mechanical impulse is transferred by an electromagnetically driven hammer, 2) measure the lens vertex relative to the shoulder of the mount with an accuracy of 250 nm and 3) do all steps which are necessary to process the lens mount within the accuracies described above.

The quality improvement of optical components for UV application demands increasing sensitivity of the instruments for optical losses measurement. In the optical region between 150 and 350 nm dedicated set-ups are normally needed to measure low-level scattering. Such instruments typically perform single-wavelength measurements, corresponding to that of the laser used. Another draw-back of such sophisticated tools is their elevated costs and the necessity of the staff specially prepared to handle with. Here we propose a novel instrument (patent pending) for measurement of spectral scattering from the high quality optical components in both UV and visible range. It permits spectral data acquisition being positioned as an attachment to a commercial spectrophotometer, and the wavelength range is limited mostly by the spectrophotometer characteristics. The advantage of low costs of a set-up constructed in the base of widely diffused commercial spectrophotometers is combined with the simplicity of its implementation. Moreover, the proposed instrument can be a base for the measurement of scattered light in a dedicated experimental set-up having the light source and the detectors different from those of a commercial spectrophotometer. Some examples of such ad-hoc set-ups are discussed here as well.

Precise absorption measurements of bulk materials and coatings upon pulsed ArF laser irradiation are presented using a compact experimental setup based on the laser induced deflection technique (LID). For absorption measurements of bulk materials the influence of pure bulk and pure surface absorption on the temperature and refractive index profile and thus for the probe beam deflection is analyzed in detail. The separation of bulk and surface absorption via the commonly used variation of the sample thickness is carried out for fused silica and calcium fluoride. The experimental results show that for the given surface polishing quality the bulk absorption coefficient of fused silica can be obtained by investigating only one sample. To avoid the drawback of different bulk and surface properties amongst a thickness series, we propose a strategy based on the LID technique to generally obtain surface and bulk absorption separately by investigating only one sample. Apart from measuring bulk absorption coefficients the LID technique is applied to determine the absorption of highly reflecting (HR) coatings on CaF₂ substrates. Beside the measuring strategy the experimental results of a AlF₃/LaF₃ based HR coating are presented. In order to investigate a larger variety of coatings, including high transmitting coatings, a general measuring strategy based on the LID technique is proposed.

The high-power Laser MegaJoule (LMJ) for inertial confinement fusion experiments that is currently under construction at CEA-CESTA in France will require a high number of large aperture Pockels cells and frequency converters made of potassium dihydrogen phosphate (KDP) and DKDP (Deuterated KDP). These optical components will be operated several times a year at fluences close to their Laser Induced Damage Threshold (LIDT) which may reduce significantly their lifetime and increase substantially the maintenance costs of the LMJ. In a global effort to reduce these costs we have designed the SOCRATE facility as a complete system for materials characterization, LIDT measurement and optics conditioning by laser to increase their lifetime. In this paper we examine the relevance of adapting the laser conditioning process to the bulk KDP quality. First the existence of heterogeneities in large KDP crystals is stressed; next the LIDTs in the different parts of the crystals using focused or collimated beams are compared. Finally we focus on the efficiency of the excimer conditioning process in the different growth sectors of KDP samples and demonstrate that for the current conditioning process the efficiency depends only weakly on the original material heterogeneities.

This paper intends to develop a measurement system to characterize photomasks for 193 nm lithography applications. Based on the VUV spectrophotometer at the Fraunhofer IOF institute, some modifications have been addressed to fulfil these special measurements. Characterizations on photomasks have been successfully carried out, which show good correlations to simulations.

Stochastic, self-organized nanostructures are produced by a low-pressure plasma treatment on the polymer polymethylmetacrylate (PMMA). The phenomena obtained by plasma treatment (structure formation and antireflective effect) are investigated regarding surface modifications, structure growth, and chemical modifications. Optically, the structure acts like a gradient layer with decreasing effective refractive index towards air, which is suitable for antireflection of PMMA.

High transparent thermoplastics have the capability to put glass out of business, especially in everyday life's optics. Their diverse nature gives rise to different antireflection principles. The reduction of surface reflection losses in polymethylmethacrylate (PMMA) is demonstrated by means of argon/oxygen plasma treatment. Since the presented reduction of reflection occurs in a wide spectral range, the technique may be applied for omnidirectional devices or curved substrates. The etching process creates a self-organized stochastic subwavelength structure at the substrate itself. The decrease in reflection is described by effective medium theory (EMT), converting the surface topology into a depth-dependent filling factor profile. In a second step this nano-scaled structure is used as the initial point for a broadband absorber by coating it with a nontransparent metal layer. A high-efficient absorber can be obtained, if the metal acts as backside coating of the double-sided plasma-treated substrate and steady-going transitions between the materials eliminating the Fresnel reflections. In practice, the magnitude of absorption depends on depth of structure as well as on the complex refractive index of the metal.

A theoretical and experimental synergic analysis of the removal of optical fiber coating has been presented. The theory of thermodynamical interfacial energy of the droplet has been introduced to analyze the process of coating removal. The theoretical results show that the liquid phase coating will splash around and will be removed because of the interaction of the vaporizing pressure and the cohesive force together. Successful experiments of coating removal have been achieved using both pulsed excimer and CO₂ lasers. The experimental results are in agreement with theoretical results.

Optical thin films, especially reflection reducing coatings, are often applied to complex surfaces, e.g. small and strongly curved optical elements that are built into optical devices like object lenses for microscopes. The performance of the device depends very much on the optical quality throughout the entire surface of the optical element. In order to measure optical parameters in defined positions of a given optical surface, a fully automated microspectrophotometer for in line quality control was developed. The microspectrophotometer consists of a Zeiss MCS 501 diode array spectrometer that is capable of fast and simultaneous data acquisition over the desired spectrum between NUV and NIR, connected via light waveguide to a Zeiss Axiostar microscope, which is operated in the reflected-light-brightfield mode, and a sample handling system that can be programmed to measure any spot on the individual surface of the optical element under examination. The size of the measured spot is in the order of about ten micrometers in diameter, allowing also characterization of defects and microscopic deviations from the desired thin film coating or optical surface. The principle and the assembly of the microspectrophotometer are presented as well as measurements of uniformity distributions of antireflection coatings on small semispheres achieved by different coating processes.

Having determined the deviations of ellipsometrical parameters for light reflected from the ribbon surface as a function of its orientation in the ribbon plane, the level of internal strain changes in the subsurface layer of Fe-based (Fe₇₅Ni₄Mo₃Si₂B₁₆ and Fe₇₀Cr₁₅B₁₅ ) amorphous metal alloys has been analyzed. Optical measurements were carried out for as-casted ribbons at 12 (Fe₇₅Ni₄Mo₃Si₂B₁₆) and 4 (Fe₇₀Cr₁₅B₁₅ ) orientations of the ribbon longitudinal axis relatively to the plane of light incidence. For each orientation phase shift Δ between p- and s-components of the polarization vector and an azimuth Ψ of the restored linear polarization have been obtained using a LEF-3M reflectometer-goniometer. From the angular dependence Δ(φ) (φ is angle of light incidence), the principal angle φ₀ of light incidence was determined. Then, by rotating the sample around a normal to its surface within 360°, the polar diagrams (so-called indicatrices of ellipsometric parameters on rotation azimuth α) have been determined. The noncircular form of the polar diagram indicates a high sensitivity to internal stress variations arising during ribbon preparation. For Fe₇₀Cr₁₅B₁₅ ribbons the long-time irradiation even by comparatively small fluencies of neutrons, causes structural relaxation and essentially influences on optical properties in the IR. It was determined that in the IR a real part of the complex dielectric function ε₁>0 at any values φ angle of light incidence and α (azimuthal orientation of the ribbon longitudinal axis with respect to the light incidence plane).

Multilayer optical devices generally suffer from two main losses sources: absorption of the materials and scattering losses, due both to volume and surface effects. The exact estimation of this latter contribution is of extreme importance for the final assessment and optimization of efficient devices. In particular, when intrinsic absorption of the materials cannot be further reduced, scattering measurements may provide useful information for improving optical device performance. In this work we investigated single SiO₂, Al₂O₃ and HfO₂ layers deposited by r.f. sputtering under different deposition conditions. These materials are being studied for implementation in multilayer dichroic mirrors for laser applications in the range from 260 to 350 nm. To avoid radiation damage, such devices need to be loss-free in the pumping and lasing region; hence, an insightful knowledge of all losses sources is fundamental.

For characterisation of non-uniform thin film coatings optical measurements should be performed with spatial resolution often much higher than that of conventional spectrophotometers. Here we present two different instruments constructed for transmittance and reflectance measurement of spatially non-uniform coatings. One of the setups is based on localized light distribution with a help of calibrated apertures, mapping needing sample displacement, while the other setup acquires the sample map 'at-once' with a CCD camera, spatial resolution being given by the pixel size. The spatial resolution ranges from 100 μm up to 2 mm for the first instrument, and is 30 μm for the second one. The spectral resolution of the first setup is about 0.5 nm in the range from 400 nm to 1700 nm, while for the second instruments it is 0.1 nm in the range 400-1000 nm. Besides the real optical performance of an optical device in terms of its spatially variable transmission and reflection, a 'mapping' of the thickness and refractive index of a single layer coating can be achieved. Comparison of the results obtained with these two instruments is given for two examples of coatings. The proposed instruments are useful tools for characterisation of both intended and undesired non-uniformity of optical coatings.

We are developing a new linewidth standard on the nanometre scale for use in the recently introduced new high-resolution optical microscopy techniques like deep ultraviolet microscopy (UVM) and confocal laser scanning microscopy (CLSM). Different types of high-resolution gratings, etched in amorphous silicon on quartz substrates, have been fabricated and evaluated using state-of-the-art UVM, CLSM, REM and AFM equipment. The produced linewidths range from about 80 nm to 2 μm. The contrast of the pattern in the UV region makes them suitable for transmission and reflection UV and laser scanning microscopy.

In this paper an advanced replication method for the production of optical components in inorganic glasses is introduced. The replication process features a non-isothermal molding procedure with short cycle time and thus reduced costs. Due to the complex thermo-mechanical behavior of the glass under non-isothermal forming conditions a detailed understanding of the process is essential for the replication of highly accurate optical components with tight tolerances. Thus the pressing process was investigated considering a certain demonstrator component to identify different stages when the gross geometry and the optical surface were formed. Then the most relevant process parameters were studied and their effects on the quality of the molded glass were quantified. It was found out that the geometrical properties, e.g. the thickness of the component is adjusted during a very short time interval after the glass contacts the mold, whereas contour and warping can be influenced for a longer time in the process. The parameters with the most significant influence on the thickness were the temperature of the glass blank and the target position of the pressing unit, whereas the duration of the glass-to-mold contact is a parameter which affects the contour of the molded component.

The modification of the microrelief and structure of the surface layers of the Co- and Fe-based amorphous metal alloys (AMA) ribbons due to thermal treatment at elevated and cryogenic temperatures and under the action of an external magnetic field is studied by methods of atomic force microscopy and spectroscopic ellipsometry. The surface structure modification processes are essentially different for these two kinds of alloys. It is explained by the magnetostriction effect which is intrinsic only for Fe- based amorphous alloy and is responsible for the optical anisotropy induced in the surface layer by the treatments. Thermal annealing of the ribbons below the crystallization temperature leads to a decrease of deformational stress and to a monotonous enhancement of the roughness parameters at the surface. Annealing of the Co-based AMA at T=425°C changes the behavior of its optical conductivity spectra in the IR from non-Drude to Drude-like. It denotes the onset of the atomic structure ordering process in the subsurface layer marked by the appearance of the microscopic regions where crystallization occurs.

One of the most actual needs in metrology is the possibility to investigate aspheres. With many optical metrology tools this is just not possible in a direct way. This task needs a completely new category of metrology tools. A new approach for this application is presented. The measuring machine performs high resolution, fast and non contact measurement of lens profiles. The geometry of the lens might be spherical or aspherical. The maximum profile length is 180 degree, maximum lens height is 50 mm. The alignment of the centre of the lens is done automatically. As an option the system may be extended into a fully 3D metrology tool.

The polishing of optical structures is as process applied to smooth surfaces while maintaining the precise shapes obtained through grinding in a process before. Until now, the macrogeometry during the polishing process is mostly influenced and adjusted by changing the kinematik, temperature of polishing fluid or by dressing the polishing pad. These exertions of influence are being applied mostly empirical. Another approach is subject of this paper: introducing an active polishing tool with a membrane like surface, which can be deformed by pneumatic actuation under maintainance of an shperic profile. This tool even allows the change of the shape of the optical surface during the polishing process.

Synchrotron Radiation (SR) mirrors are ultra precision optical components with very high requirements to shape accuracy and smoothness. According to the special functions mirrors with different shapes are used. The dimensions of such mirrors extend from some tenfold of millimetres to a length of more than one meter. Commonly such mirrors are made of single crystal silicon, Zerodur^(R), ULE^(R) glass and in rare cases of silicon carbide, special steel or Glidcop^(R). Some considerations lead to the result that also tungsten is an interesting alternative material for SR-mirrors. The paper presents the design, some results of the ultra precision machining and some functional parameters of the SR-mirror prototype.

Light angle-resolved and total integral scattering (ARS and TIS) have been used for several decades to probe surface roughness and heterogeneities in optical multilayers and substrates. We present a summary of results reached in laser metrology techniques in our Institute. Elaboration of the optical surface finish technology requires non-destructive sensitive measurement methods subsequent development. Need optical surfaces for precision quantum electronics devices are usually composed of irregularities smaller than 1 nm "high" with "slope" of low gradient of perhaps 0,001 rad relative to the mean surface and destructive layer thickness about tens of nanometres. There are described application of ARS method and automatically device, based on this method for testing optically transparent surfaces by scattering indicatrix analysing. We discuss the problem: how it can measure surfaces roughness of inside scattering materials substrates and separate of surface roughness and substrates material heterogeneity effects. We touched up the questions: how surface rms-roughness of substrates correlates with scattering of mirrors and how smooth surfaces of substrates correlate with back specula scattering of ion-sputtering on these substrates mirrors. In some cases of our researches we compared the light scattering measurement results with the results of atomic force microscope (AFM) and X-rays scattering (XRS) measurement methods.

Optical State Estimation provides a framework for both separating errors in test optics from the target system and deducing the state of multiple optics in a telescope beam train using wavefront as well as pre-test component measurements including the knowledge of their level of error. Using this framework, we investigate the feasibility of simplifying the interferometric alignment configuration of NASA's James Webb Space Telescope, a large segmented-aperture cryogenic telescope, using a single, static auto-collimating flat instead of six such flats, resulting in a reduced sub-aperture sampling.

Why do we need to characterize surfaces and specially scattering of surfaces? In many industries including the automotive industry, interaction of light with materials is very important, in headlamps, tail lamps, dashboards, and the simulations made by designers, developers with their illumination design software, their realistic rendering software need scattering data to perform simulations and get results. Unfortunately, only theoretical data are available right now, and simulation results are not relevant of reality. It is why we have developed the REFLET Bench to answer all these problems.

Magnetorheological Finishing (MRF) is commonly used to finish high quality optical surfaces. The process is based on a magnetorheological fluid, which stiffens in a magnetic field and thus may be used as a polishing tool. The fluid removal characteristic depends on several parameters, for example the magnetic field strength or the relative velocity between workpiece and polishing tool. Another parameter is the fluid itself. Different compositions of polishing abrasives result in different removal characteristics. At the University of Applied Sciences Deggendorf, five different magnetorheological polishing fluids have been analysed. The results of the research are scanning electron microscope analyses as well as spectra analyses. The removal characteristic for each fluid has been determined for different glass materials. Finally, the fluid conditions during polishing have been analysed. For this purpose, the fluid flow rate, the fluid pressure and the fluid viscosity have been investigated.

Spectroscopic ellipsometry (SE) with microscopic measurement spot is applied to extract geometrical parameters of a bi-periodic array of holes patterned on the top of an Si wafer, namely the holes' diameter and depth, while the period of the patterning is assumed same as the value intended by the manufacturer. The SE response of the structure is simulated by the rigorous coupled-wave analysis implemented as the Airy-like internal reflection series, whose detailed description for the case of 2D gratings is provided with a brief demonstration of its convergence properties. The result of the extraction by SE is compared with results obtained by scanning electron microscopy (SEM) with reasonable agreement. The difference between some of the SE, SEM, and nominal parameters are discussed and the possibility to increase the accuracy of SE-based metrology is suggested.