This PDF file contains the front matter associated with SPIE Proceedings Volume 11853, including the Title Page, Copyright information, and Table of Contents.

The joining of optical glasses is a challenge even with the latest technology. Welding with ultrashort pulsed lasers is a way to join similar or dissimilar glasses without additives or macroscopic thermal tensions. The laser beam is focused through the work piece on the interface to be welded. Due to the high intensity in the laser focus, the beam is absorbed via nonlinear effects in a volume with about 20 µm in diameter. Several laser pulses heat up the material to the working point, while the thermal conductivity limits the heat affected zone well below 1 mm. This process is usually conducted with microscope objectives. Their short working distance limits the thickness of the work piece, the usable laser power and the feed rate of the process. To increase the possible dimensions of the welding partners and the process speed to industrial levels, we present USP-welding with a galvoscanner and a common F-theta-lens. Despite self-focusing effects, our experiments show that the process is stable and controllable. Furthermore, filamentation of the laser beam occurs and long cylindrical weld zones of some micrometers diameter and several hundreds of micrometers height are generated. The enormous length of this molten zone significantly lowers the demands on the work piece adjustment. Tensile tests were conducted on the welded samples. The tests show that the weld can reach a breaking strength in the order of magnitude of the base material.

Atmospheric Plasma Jet Machining is performed on Borosilicate Crown Glass. A fluorine containing plasma jet is suitable for the etching of the material. A substrate surface temperature of about 325°C during processing is necessary for a controlled removal. The figure error can be corrected by a dwell time based deterministic process. The resulting surface roughness depends on the surface temperature of the processed sample.

Chromatic aberrations are limiting the imaging performance of lenses. The classical way to correct of chromatic aberrations using flint and crown glasses adds volume, surfaces, and cost to the optical system. We present a novel approach to the problem based on diffractive optical elements (DOE) which can be applied as thin layers of silicone on glass substrates. We explain the optical design, the tooling required for highly efficient DOEs and the manufacturing process.

Technical systems are constantly getting reduced in size while functions are to be improved. The requirements for hightech components exceed the feasible limits of production technologies. Integrated precision components must meet everincreasing demands with regard to optical and geometric properties. Conventional technologies of glass machining often cannot withstand these requirements. Grinding, lapping and polishing processes are realized on separate machines. Thus, the manual change of components between the machines and constraints in machine kinematics result in significant loss of accuracy as well as restrictions in design and functionality.   To meet the requirements, ShapeFab developed a more efficient manufacturing process for high-precision components made of glass. All previously separated manufacturing steps are combined on one machine. By means of high-precision 5- axis CNC jig grinding and corresponding integration of CAD-CAM chain, processes of finest machining and polishing can be fully combined. This leads to application of optically effective surfaces to almost any geometrical element. In addition, the machining of complex geometries can be accelerated due to highly automated processes, even in low volume production.   With our technology a new generation of components with structures from 300 μm is available. High-precision parts can be designed smaller, lighter and multifunctional. For example, fixing geometries can be directly integrated in optical functional and freeform areas. This allows the components to be integrated into the final application with μm-precision, even without fixtures or further adjustment elements. The whole technical system can be designed compactly and costs for additional mechanical components can be saved.   Applications can be found in almost all areas of photonics. Especially requirements from the semiconductor industry, optics, medical technology and laser technology can be fulfilled.

We investigated a novel approach for building measurement routines for measuring free form optics including fiducials based on an intuitive semi-automatic teach-in mode that requires no programming skills. An initial software version for use with the MarForm MFU 200 Aspheric 3D multi-sensor precision optics measuring station was developed and tested. In this paper, we describe the structure and the workflow of the software and show measurement results of test samples.

Modern optical designs rely on a mix of spherical and aspherical lenses to reduce the element count, weight, overall price and assembly effort of optics. Aspherical elements are commonplace in specialized, high-performance laboratory and medical equipment as well as consumer electronics such as smartphone cameras. To produce these lenses, manufacturing shops need to have the necessary metrology tools, such as stitching interferometers, tactile measuring machines or null correctors for interferometers e.g. CGHs. This requirement may be an economic hurdle for smaller optical shops, which are specialized on small batch or single-item production. Therefore, researchers at THD work on a solution to provide a new class of economic, contactless, light-based measuring machines for aspherical as well as spherical or flat surfaces. The proposed machine is in principle a wavefront sensor and employs for this purpose an angle-sensitive filter e.g. a metallic interference filter. In this paper the steps to gain the prerequisite calibration of angle-sensitive filters are laid out. The commissioning of a filter transmission measuring machine is described. This machine consists of a laser-based illumination system, an angle measurement table, a telecentric lens with a scientific CMOS camera as well as data acquisition and data analysis software. Several “lessons learned” regarding the correct setup and alignment of the system are described. A first filter is measured and a diagram of transmission against angle is presented. A perspective of future work on the system, i.a. the usage of a Shack-Hartmann sensor for an orthogonal alignment of the beam axis with the rotational axis, is given.

Testing of an X-ray mirror by a point diffraction interferometer (PDI) D7 with two beams is described. Thanks to the two independent test and reference beams, mirrors metrology using the D7 coupled with accessory optics becomes straightforward and reliable. Therefore procedure of systematic error removal and sub-aperture measurements with stitching are simplified. In this paper, we describe the main technique to achieve high accuracy of stitching sub-aperture wavefronts, followed by further perspectives of the described instrument.

SIOS Meβtechnik GmbH developed a universal interferometrical profilometer for 3D measurements of freeform optics topography. Due to the measurement principle using a scanning differential interferometer, no expensive and individually shaped reference optics are required. All optic shapes such as plane-,spherical-, and freeform-optics with local slopes up to 7 mrad and sizes up to 100 × 100 mm² can be measured with sub-nanometer resolution. The capability of the setup has been proven by measurements of highly precise machined silicon mirrors (plane and spherical). A maximum of ± 3 nm peak-valley deviation between two subsequent measurements of a 30 mm × 100 mm plane mirror topography has been achieved, which proves a very good repeatability. Furthermore, measurement results show very good accordance with those from Fizeau interferometer measurements of this precision plane mirror. The maximum deviation was ± 10 nm, which is a hint to a very good accuracy of our measurements. Furthermore, form parameters such as the radii of spherical mirrors can be determined precisely due to the interferometer-based synchronous measurements of the x- and y- positions of the z- topography. A reproducibility of 1.4 × 10^-4 of the radius measurements of a 29 m radius mirror was achieved, whereat the mirror was measured on different supports and in different orientations.

The design of optical systems has two main tasks: (a) their optimal optical performance and (b) their optimal producibility; whereby the latter has to comply with the "magic triangle" of optical performance quality, fabrication cost and manufacturing throughput. Unfortunately, for decades there has been a major mismatch in designing optical systems. On one hand, optical system designers are well supported by State-of-The-Art optical design software tools while on the other hand, the design of optical fabrication chains and their cost, which is strongly interlinked with the parameters and tolerances of the optical system design, is still today completely depending on humans experiences and knowledge. Consequently, while optical system designs are well optimized for optical system performance, their optimization for optimal producibility and manufacturing chain design is not possible during the design phase of the optical system itself. This paper reports on the application of a novel approach to optical design strategies. Within a Swiss research project called PanDao, a new type of software tool was developed enabling the integration of producibility analyses and fabrication chain optimizations into the optical design process. PanDao reads in lens parameters and tolerances as described in the ISO 10110 standards and generates the optimal fabrication chain at minimum cost, taking more than 300 optical fabrication techniques into account.

The evolution of the old standard DIN 3140 for the tolerances of surface form deviations to the actual standard ISO 10110-5 introduces a more complex description of the form deviations and their tolerances. The drawing standard ISO 10110-5 is accompanied by the measurement standard ISO 14999-4, that complements the old test glass measurements by interferometric test methods. The different types of surface deformations have different impact on the performance of an optical system, and the selected tolerances must limit the image degradation within the specified limits. For some specific applications the most appropriate description of the relevant surface deformation is not yet foreseen in the actual standard, but future versions of the standard might include reasonable extensions.

Liquid-based lenses are of notable interest for the realization of prototypes, small batch series and even mass-product articles as for example micro lens arrays or low-cost optics. Hence, quite a number of different approaches for the manufacture of such lenses are in hand. The focal length of liquid lenses can be customized by the choice of the used liquid, a modification of its viscosity, for example via heating, substrate coating or overhead storing and curing. In this contribution, we present a further approach based on plasma treatment of the substrate surface where two different effects are generated by the use of different process gases. After treatment, optical cement is applied to the surfaces, forming a plano-convex lens due to surface tension. Argon plasma treatment leads to a reduction of the contact angle and an increase in the focal length of the lens in the course of treatment. The opposite effect, an increase in contact angle and a decrease in focal length, respectively, occurs when using octafluorocyclobutane as process gas. The possible range of currently realizable focal lengths and the particularly underlying effects are presented in this contribution.

Optics and photonics are considered as an enabling technology for innovations in other technological fields (e. g. astronomy, medicine, military, …). Their first applications date back to jewellery processing in ancient times. In the medieval age Vikings on Gotland (1050) buried the Visby lenses. They have a quality of workmanship and imaging comparable to a high quality lens made in the mid-20th century. The specific use of spectacles to correct long-sightedness or presbyopia is known from the 13th century. Around the transition from the 16th to the 17th century, the microscope and the telescope were invented, combining several lenses for the first time. This shows that the exploitation of the optical properties of materials can be dated back very early in human history. In particularly, today`s optics industry is still based on personal knowledge which results in a relatively workmanship production environment. The challenges of globalisation and the current pandemic situation demonstrate that increasing the degree of automation is a possible way to keep a leading position in the market. This is not only important due to the high quality of optical components but also by enabling competitive prices for production through reducing the labour costs. The third industrial revolution established the digitalisation of production and the usage of CNC-machinery. In most industries including optics industries this is the status quo of production. The target of industry 4.0 and internet of things is to lead into a new industrial revolution. The German government developed the buzzword “Industrie 4.0” (eng. Industry 4.01 ). This concept includes the contradiction of mass production and production according to individual customer requests. This should be carried out by connecting all production units with the goal of an intelligent factory. Among other things this includes seamless monitoring of the manufacturing processes along all steps and remote access to involved machines. A further target is manufacturing under the constraint of a small batch size down to one piece. This publication aims to present the current situation in the manufacturing of optical components and compare this with manufacturing of metallic components. It will outline, which measures are necessary to ensure a comprehensive transformation of the optical industry in accordance with the Industry 4.0 idea and which benefits can be expected.

In this paper we present a feasible variant of a device for in-process roughness measurement during an optical polishing process. The system, already presented as Tirm respectively I-Tirm, has been technically varied and can now be integrated into almost any lever polishing process with little effort. This enables new possibilities regarding real-time optical manufacturing process monitoring and optimization.

Deflectometric measurements using V-SPOT technology has been proven to achieve accurate surface profiles for aspheres at moderate cost and low preparation effort. In order to extend the resolution limit, the optical and mechanical device has been improved to provide on the one side topography information in the slope domain at high accuracy (< 5 μrad) and an improved lateral resolution (< 0,2 mm) to cover surface profile errors in the mid-spatial-frequency range from 1 to 10 mm^-1. Within this publication we are providing the experimental setup and the measurement procedures to achieve production relevant information about the surface quality. Slope deviations of aspheric samples (glass and metal) are analyzed in angular spectral components and the surface profile is compared with interferometric data to proof accuracy and lateral resolution of our device. As final conclusion we outlook for further improvements of the proposed device to allow full control of form deviation and mid-spatial frequency errors.

The aim of the research was the development of a measurement and analysis method that enables the detection of errors and malfunctions within a machine tools and in the manufacturing process using acoustic sensors (microphones).