This PDF file contains the front matter associated with SPIE Proceedings Volume 10375, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

Advances in manufacturing and measuring technology are making the use of freeform mirrors more practical than in the recent past. New degrees of freedom make it possible for designers to improve image quality while increasing the field of view and avoiding obscurations. But other issues arise when one designs a system with several mirrors, particularly packaging and clearance concerns: one must ensure that none of the mirrors gets in the way of the beam from any of the others, and one must consider the coordinate system in which the shapes are defined and in which they are measured, which are not necessarily the same. Addressing these concerns requires new computational tools.

A hyperspectral imaging system is proposed for early study of skin diagnosis. A stable and high hyperspectral image quality is important for analysis. Therefore, a light guide sleeve (LGS) was designed for the embedded on a hyperspectral imaging system. It provides a uniform light source on the object plane with the determined distance. Furthermore, it can shield the ambient light from entering the system and increasing noise. For the purpose of producing a uniform light source, the LGS device was designed in the symmetrical double-layered structure. It has light cut structures to adjust distribution of rays between two layers and has the Lambertian surface in the front-end to promote output uniformity. In the simulation of the design, the uniformity of illuminance was about 91.7%. In the measurement of the actual light guide sleeve, the uniformity of illuminance was about 92.5%.

This talk will review the design principles and techniques behind imaging spectrometer design leading to high spectroscopic data fidelity. These involve optical design, tolerancing and alignment, stray light, as well as methods of assessment and verification. Examples from deployed systems illustrate the methods. Some recent results on the use of freeform surfaces will also be shown.

Conventional round spot quadrant detector trackers are inherently non-linear. This non-linearity requires multiple iterations to converge onto perfect alignment with the object tracked. We created a system that generates a square spot. The convolution of a square spot with a circle, generated by the quadrant detector, allows this spot to achieve perfect alignment in one iteration. This invention is thus essential to any system that requires speed and accuracy. In this paper, we introduce the theory behind the square spot as well as the design of our linear optical quadrant detector tracking technology.

A multi-band pass filter array was proposed and designed for short wave infrared applications. The central wavelength of the multi-band pass filters are located about 905 nm, 950 nm, 1055 nm and 1550 nm. In the simulation of an optical interference band pass filter, high spectrum performance (high transmittance ratio between the pass band and stop band) relies on (1) the index gap between the selected high/low-index film materials, with a larger gap correlated to higher performance, and (2) sufficient repeated periods of high/low-index thin-film layers. When determining high and low refractive index materials, spectrum performance was improved by increasing repeated periods. Consequently, the total film thickness increases rapidly. In some cases, a thick total film thickness is difficult to process in practice, especially when incorporating photolithography liftoff. Actually the maximal thickness of the photoresist being able to liftoff will bound the total film thickness of the band pass filter. For the application of the short wave infrared with the wavelength range from 900nm to 1700nm, silicone was chosen as a high refractive index material. Different from other dielectric materials used in the visible range, silicone has a higher absorptance in the visible range opposite to higher transmission in the short wave infrared. In other words, designing band pass filters based on silicone as a high refractive index material film could not obtain a better spectrum performance than conventional high index materials like TiO₂ or Ta₂O₅, but also its material cost would reduce about half compared to the total film thickness with the conventional material TiO₂. Through the simulation and several experimental trials, the total film thickness below 4 um was practicable and reasonable. The fabrication of the filters was employed a dual electric gun deposition system with ion assisted deposition after the lithography process. Repeating four times of lithography and deposition process and black matrix coating, the optical device processes were completed.

The fluorescence of optical glasses is a property that needs to be taken into account in optical designs for life science applications. Many optical glasses from SCHOTT show a very low intrinsic or auto-fluorescence. The fluorescence depends mainly on the applied excitation wavelength and the optical glass type. The fluorescence of optical glasses is usually defined as the quotient of the integral of the emission spectrum with the integral of the emission spectrum of a reference glass. This definition does not give any information about the actual quantum efficiency of the fluorescence. In this presentation recent data on the integral fluorescence of SCHOTT optical glasses are presented. Additionally, first measurements of the quantum efficiency of SCHOTT optical glasses are presented and compared to the standard method.

This paper reports measurements of the refractive index of Homosil (Heraeus) over the wavelength range of 0.34—3.16 μm and temperature range of 120—335 K. These measurements were performed by using the Cryogenic High Accuracy Refraction Measuring System (CHARMS) facility at the NASA’s Goddard Space Flight Center. These measurements were in support of an integrated Structural-Thermal-Optical-Performance (STOP) model that was developed for a fieldwidened Michelson interferometer that is being built and tested for the High Spectral Resolution Lidar (HSRL) project at the NASA Langley Research Center (LaRC). The cryogenic refractive index measurements were required in order to account for the highly sensitive performance of the HSRL instrument to changes in refractive index with temperature, temperature gradients, thermal expansion, and deformation due to mounting stresses. A dense coverage of the absolute refractive index over the aforementioned wavelength and temperature ranges was used to determine the thermo-optic coefficient (dn/dT) and dispersion relation (dn/dλ) as a function of wavelength and temperature. Our measurements of Homosil will be compared with measurements of other glasses from the fused silica family studied in CHARMS as well as measurements reported elsewhere in the literature.

In the aberration analysis of a wavefront over a certain domain, the polynomials that are orthogonal over and represent balanced wave aberrations for this domain are used. For example, Zernike circle polynomials are used for the analysis of a circular wavefront. Similarly, the annular polynomials are used to analyze the annular wavefronts for systems with annular pupils, as in a rotationally symmetric two-mirror system, such as the Hubble space telescope. However, when the data available for analysis are the slopes of a wavefront, as, for example, in a Shack– Hartmann sensor, we can integrate the slope data to obtain the wavefront data, and then use the orthogonal polynomials to obtain the aberration coefficients. An alternative is to find vector functions that are orthogonal to the gradients of the wavefront polynomials, and obtain the aberration coefficients directly as the inner products of these functions with the slope data. In this paper, we show that an infinite number of vector functions can be obtained in this manner. We show further that the vector functions that are irrotational are unique and propagate minimum uncorrelated additive random noise from the slope data to the aberration coefficients.

With the wide-spread availability of electromagnetic; i.e., vector, analysis codes for describing the diffraction of electromagnetic waves by periodic grating structures, the insight and understanding of non-paraxial parametric diffraction grating behavior afforded by approximate methods (i.e.; scalar diffraction theory) is being ignored in the education of most optical engineers today. In this paper we show how the recent linear systems formulation of non-paraxial scalar diffraction theory allows the development of a scalar parametric diffraction grating analysis for sinusoidal reflection (phase) gratings with arbitrary groove depths and arbitrary non-paraxial incident and diffracted angles. This scalar parametric analysis is remarkably accurate as it includes the ability to redistribute the energy from evanescent orders into the propagating ones, thus allowing the calculation of non-paraxial diffraction efficiencies to be predicted with an accuracy usually thought to require rigorous electromagnetic theory. These scalar parametric predictions of diffraction efficiency compare well with rigorous predictions for a variety of non-paraxial diffraction grating configurations.

MTF is one of the most common metrics used to quantify the resolving power of an optical component. Extensive literature is dedicated to describing methods to calculate the Modulation Transfer Function (MTF) for stand-alone optical components such as a camera lens or telescope, and some literature addresses approaches to determine an MTF for combination of an optic with a detector. The formulations pertaining to a combined electro-optical system MTF are mostly based on theory, and assumptions that detector MTF is described only by the pixel pitch which does not account for wavelength dependencies. When working with real hardware, detectors are often characterized by testing MTF at discrete wavelengths. This paper presents a method to simplify the calculation of a polychromatic system MTF when it is permissible to consider the detector MTF to be independent of wavelength.

In a recent paper, we compared the diffraction and geometrical optical transfer functions (OTFs) of an optical imaging system, and showed that the GOTF approximates the DOTF within 10% when a primary aberration is about two waves or larger [Appl. Opt., 55, 3241–3250 (2016)]. In this paper, we determine and compare the times to calculate the DOTF by autocorrelation or digital autocorrelation of the pupil function, and by a Fourier transform (FT) of the point-spread function (PSF); and the GOTF by a FT of the geometrical PSF and its approximation, the spot diagram. Our starting point for calculating the DOTF is the wave aberrations of the system in its pupil plane, and the ray aberrations in the image plane for the GOTF. The numerical results for primary aberrations and a typical imaging system show that the direct integrations are slow, but the calculation of the DOTF by a FT of the PSF is generally faster than the GOTF calculation by a FT of the spot diagram.

A technique for decomposing the Optical Transfer Function (OTF) into a novel set of basis functions has been developed. The decomposition provides insight into the performance of optical systems containing both wavefront error and apodization, as well as the interactions between the various components of the pupil function. Previously, this technique has been applied to systems with circular pupils with both uniform illumination and Gaussian apodization. Here, systems with annular pupils are explored. In cases of annular pupil with simple defocus, analytic expressions for the OTF decomposition coefficients can be calculated. The annular case is not only applicable to optical systems with central obscurations, but the technique can be extended to systems with multiple ring structures. The ring structures can have constant area as is often found in zone plates and diffractive lenses or the rings can have arbitrary areas. Analytic expressions for the OTF decomposition coefficients again can be determined for ring structures with constant and quadratic phase variations. The OTF decomposition provides a general tool to analyze and compare a diverse set of optical systems.

For realization of a miniaturized optical gyroscope the precise assembly of optical micro components is crucial. To detect the rotation rate the laser beam must circulate many times and not leave the resonator due to small misalignments. The assembly of a passive free space triangular ring resonator in which the light can circulate by reflections at three mirrors is investigated. The beam path encloses an area of about 100 mm². The resonator shall be activated by an external light source at 1550 nm, a wavelength at which silicon is translucent and allowing to couple light into the resonator through the silicon mirrors. To utilize an inherent mirror alignment two of the mirrors are fabricated with a micro manufacturing process within the same crystal by wet etching resulting in very perfect {111} facets. The etching solution was optimized with respect to process time and smoothness of the mirror surfaces. To further increase the reflectivity of the mirrors different kinds of coatings are tested. With these two perfectly positioned mirrors the assembly challenge reduces to 3DOF alignment of a third {100} mirror for which a well-designed adjustable spacer is developed. In first tests resonance in a linear cavity test setup is demonstrated already.

In this paper, we present a wide-angle and compact camera module that consists of microlens array with different focal lengths on curved surface. The design integrates the principle of an insect’s compound eye and the human eye. It contains a curved hexagonal microlens array and a spherical lens. Compared with normal mobile phone cameras which usually need no less than four lenses, but our proposed system only uses one lens. Furthermore, the thickness of our proposed system is only 2.08 mm and diagonal full field of view is about 100 degrees. In order to make the critical microlens array, we used the inkjet printing to control the surface shape of each microlens for achieving different focal lengths and use replication method to form curved hexagonal microlens array.

Lasers are a promising high accuracy tool to make small holes in composite or hard material. They offer advantages over the conventional machining process, which is time consuming and has scaling limitations. However, the major downfall in laser material processing is the relatively large heat affect zone or number of molten burrs it generates, even when using nanosecond lasers over high-cost ultrafast lasers. In this paper, we constructed a nanosecond laser processing system with a 532 nm wavelength laser source. In order to enhance precision and minimize the effect of heat generation with the laser drilling process, we investigated the geometric shape of optical elements and analyzed the images using the modulation transfer function (MTF) and encircled energy (EE) by using optical software Zemax. We discuss commercial spherical lenses, including plano-convex lenses, bi-convex lenses, plano-concave lenses, bi-concave lenses, best-form lenses, and meniscus lenses. Furthermore, we determined the best lens configuration by image evaluation, and then verified the results experimentally by carrying out the laser drilling process on multilayer flexible copper clad laminate (FCCL). The paper presents the drilling results obtained with different lens configurations and found the best configuration had a small heat affect zone and a clean edge along laser-drilled holes.

Liquid crystal (LC) lenses have attracted much attention, owing to the light weight and an adjustable focal length without mechanically moving parts. Among the developed LC lenses, the hole-patterned LC lens has a convenient fabrication process, a simple addressing scheme, and widely tunable focal range. Nonetheless, a thick dielectric layer (TDL) has to be inserted between the hole-patterned electrode and the LC layer to distribute the fringing electric field throughout the center of the aperture hole (AH). However, the inserted TDL significantly increases the operation voltage of the LC lens. In this paper, we propose a hole-patterned LC lens with a wide diameter of 6 mm. In our design, a floating ring electrode (FRE) is embedded into the interface between the dielectric layer and the LC layer. This structure confines the electric field in the hole patterned area, therefore assists in distributing the fringing electric field throughout the LC layer and thus assists in tilting the LCs in the AH center of the lens. Therefore, the dielectric layer used in the conventional hole-patterned LC lens can be effectively decreased. The decreased thickness of the dielectric layer provides the FRE LC lens with the advantages of lower operation voltage and large tunable focal range. With a voltage of 40 V, the introduced floating ring electrode modulates the phase retardation of the LC lens in a nearly perfect quadratic form with wavefront error approaching 0.07 . The design principle, simulation and fabrication of the LC lens are demonstrated in this paper.

A traditional zoom system is composed of several elements moving relatively toward other components to achieve zooming. Unlike tradition system, an electrically control zoom system with liquid crystal (LC) lenses is demonstrated in this paper. To achieve zooming, we apply two LC lenses whose optical power is controlled by voltage to replace two moving lenses in traditional zoom system. The mechanism of zoom system is to use two LC lenses to form a simple zoom system. We found that with such spherical electrodes, we could operate LC lens at voltage range from 31V to 53 V for 3X tunability in optical power. For each LC lens, we use concave spherical electrode which provide lower operating voltage and great tunability in optical power, respectively. For such operating voltage and compact size, this zoom system with zoom ratio approximate 3:1 could be applied to mobile phone, camera and other applications.

This paper presents a refractive optical system consisting of two lens bodies with helical surface structures, which allows for tuning the optical refraction power by means of a mutual rotation of the lens bodies around the optical axis. Thus, the refraction power can be tuned continuously in a certain range. The helical surfaces are shaped by changing the radius of curvature as a function of to the polar angle. Combination of such two surfaces results in an optics with refraction power being tunable by a mutual rotation. This optical system is multifocal with at least two sectors with different individually tunable refraction powers. To obtain a monofocal rotation optics, obscuration of one of the lens sectors is necessary. Conventional lens systems providing tunable refraction power do so by mutual axial or lateral shift of the lenses or the lens parts. Hence, additional space for lens movement is needed in the mechanical design. Since the rotational optics allows for adjustment of the refraction power by a mutual rotation of the lens parts, no displacement of lenses is needed and a more compact design is obtained.

Bullet-shaped LEDs are commonly used in self-luminous traffic signs as LED-dotted matrices due to their low cost, simplicity, robustness, and ease of installation. We proposed a simple low-cost method that creates a model suitable for the high manufacturing tolerance found in bullet-shaped LEDs. The method starts from measuring multiple one-dimensional angular intensity patterns at interested distances from multiple LEDs to form a database, including distances at 10, 15, 20, 25, 35, 50, and 100 mm. Their normalized cross-correlations are then calculated to find the batch that has the most similarity and base our model off that batch. Finally, we validate the model via Monte Carlo simulations in comparison to the original one-dimensional angular intensity patterns in the database. The platform demonstrated to obtain an average of 99% in normalized cross correlation between different batches of the same model LED, and a model of that LED is currently under development.

To investigate the legibility and visual comfort of LED traffic signs, an ergonomic experiment is performed on four custom-designed LED traffic signs, including three self-luminous ones as LED lightbox, LED backlight and regional LED backlight, and one non-self-luminous sign with external LED lighting. The four signs are hanged side-by-side and evaluated by observers through questionnaires. The signage dimension is one-sixth of the real freeway traffic signs, and the observation distance is 25 m. The luminance of three self-luminous signs is 216 cd/m². The illuminance of external LED lighting is 400 lux on the traffic sign. The ambient illuminance is 2.8 and 6.0 lux in two rounds. The results show that self-luminous traffic signs provide superior legibility, visual comfort and user preference than the non-self-luminous one. Among the three self-luminous signs, regional LED backlight is most susceptible to the ambient illumination. LED lightbox has significantly better preference score than LED backlight under darker ambient lighting. Only LED lightbox has significantly better visual comfort than external LED lighting in the brighter environment. Based on the four LED traffic signs evaluated in this study, we suggest LED lightbox as the prior choice. Further investigations on the effect of ambient illumination and other designs of self-luminous traffic signs are in progress.

Now that LEDs have massively invaded the illumination market, a clear trend has emerged for more efficient and targeted lighting. The project described here is at the leading edge of the trend and aims at developing an evaluation board to test smart lighting applications. This is made possible thanks to a new liquid crystal light modulator recently developed for broadening LED light beams. The modulator is controlled by electrical signals and is characterized by a linear working zone. This feature allows the implementation of a closed loop control with a sensor feedback. This project shows that the use of computer vision is a promising opportunity for cheap closed loop control. The developed evaluation board integrates the liquid crystal modulator, a webcam, a LED light source and all the required electronics to implement a closed loop control with a computer vision algorithm.

The design of a secondary optical lens for light beam shaping using the transformation method is performed by transforming the light source energy distribution using the concepts of energy conservation and light energy mapping. Using these concepts creates a dependency relation between the output optical performance and the luminous intensity distribution of the light source. This relation leads to errors on the optical performance due to the fabrication misalignment between the light source and the secondary optical lens. On the other hand, in the illumination applications, the integration method has been proved to be an efficient method for achieving a high degree of homogenized luminous intensity distribution by integrating and superimposing the light source energy over the illuminated objects. In signal lighting applications, the luminous intensity distribution must meet the requirements regarding the brightness perception of users over the spatial angular distribution, not the illumination of objects. In this paper, the integration method is combined with the transformation method to design a refractive lens-array for signal lighting applications. The difference between the two methods is described, presenting the advantages of the combination process. Design procedures are explained in detail including the lens-array modeling. The optical performance is investigated using an optical ray tracing. Finally, the influence of the misalignment between the light source and the refractive lens-array is measured.

MWIR (Mid-Wave Infrared) spectroscopy shows a large potential in the current IR devices market, due to its multiple applications, such as gas detection, chemical analysis, industrial monitoring, combustion and flame characterization. It opens this technique to the fields of application, such as industrial monitoring and control, agriculture and environmental monitoring. However, a major barrier, which is the lack of affordable specific key elements such a MWIR light sources and low cost uncooled detectors, have held it back from its widespread use. In this paper an uncooled MWIR detector combined with image enhancement technique is reported. This investigation shows good results in gas leakage detection test. It also verify the functions of self-developed MWIR lens and optics. A good agreement in theoretical design and experiment give us the lessons learned for the potential application in infrared satellite technology. A brief discussions will also be presented in this paper.

In this paper, the optical design of an athermalised dual field of view step zoom optical system in MWIR (3.7μm – 4.8μm) is described. The dual field of view infrared optical system is designed based on the principle of passive athermalization method not only to achieve athermal optical system but also to keep the high image quality within the working temperature between -40°C and +60°C. The infrared optical system used in this study had a 320 pixel x 256 pixel resolution, 20μm pixel pitch size cooled MWIR focal plane array detector. In this study, the step zoom mechanism, which has the axial motion due to consisting of a lens group, is considered to simplify mechanical structure. The optical design was based on moving a single lens along the optical axis for changing the optical system’s field of view not only to reduce the number of moving parts but also to athermalize for the optical system. The optical design began with an optimization process using paraxial optics when first-order optics parameters are determined. During the optimization process, in order to reduce aberrations, such as coma, astigmatism, spherical and chromatic aberrations, aspherical surfaces were used. As a result, athermalised dual field of view step zoom optical design is proposed and the performance of the design using proposed method was verified by providing the focus shifts, spot diagrams and MTF analyzes’ plots.

The design of the rigid contact lens (CL) with slope-constrained Q-type aspheres for myopia correction is presented in this paper. The spherical CL is the most common type for myopia correction, however the spherical aberration (SA) caused from the pupil dilation in dark leads to the degradation of visual acuity which cannot be corrected by spherical surface. The spherical and aspheric CLs are designed respectively based on Liou’s schematic eye model, and the criterion is the modulation transfer function (MTF) at the frequency of 100 line pair per mm, which corresponds to the normal vision of one arc-minute. After optimization, the MTF of the aspheric design is superior to that of the spherical design, because the aspheric surface corrects the SA for improving the visual acuity in dark. For avoiding the scratch caused from the contact profilometer, the aspheric surface is designed to match the measurability of the interferometer. The Q-type aspheric surface is employed to constrain the root-mean-square (rms) slope of the departure from a best-fit sphere directly, because the fringe density is limited by the interferometer. The maximum sag departure from a best-fit sphere is also controlled according to the measurability of the aspheric stitching interferometer (ASI). The inflection point is removed during optimization for measurability and appearance. In this study, the aspheric CL is successfully designed with Q-type aspheres for the measurability of the interferometer. It not only corrects the myopia but also eliminates the SA for improving the visual acuity in dark based on the schematic eye model.

We designed a compact middle-wave infrared (MWIR) lens with a large focal length ratio (about 1.5:1), used in the 3.7 to 4.8 μm range. The lens is consisted of a compact front group and a re-imaging group. Thanks to the compact front group configuration, it is possible to install a filter wheel mechanism in such a tight space. The total track length of the lens is about 50mm, which includes a 2mm thick protective window and a cold shield of 12mm. The full field of view of the lens is about 3.6°, and F number is less than 1.6, the image circle is about 4.6mm in diameter. The design performance of the lens reaches diffraction limitation, and doesn’t change a lot during a temperature range of -40°C~+60°C. This essay proposed a stepwise design method of infrared optical system guided by the qualitative approach. The method fully utilize the powerful global optimization ability, with a little effort to write code snippet in optical design software, frees optical engineer from tedious calculation of the original structure.

The possibility of building a spectrometer based on a flat two-dimensional (crossed) grating is being considered. The most suitable layout for this is the Czerny - Turner, where a spectral image lies in the plane. In this paper an attempt to compensate for the transverse aberrations is made by using a diffraction grating with variable spacing grooves in both sections and aspheric mirror elements of layout, including ones having a freeform surface. Using crossed grating greatly simplifies the device layout and may be particularly effective when used in the ultraviolet and infrared regions of the spectrum, due to a small choice of transmissive materials for manufacturing spectral prisms. This paper gives examples of such case.

In this paper a well-known approach is used for calculation of off-axis three-mirror telescope. It includes usage of conic cross-sections properties, each of the sections forming a stigmatic image. To create a compact optical system, a flat mirror aberration corrector is introduced, which is at later stage transformed into a free-form surface in order to compensate field aberrations. Similarly, one can introduce such a corrector in finalized layout for its further optimization and getting a suitable form, including the conversion of multimirrors axial optical system into decentered one. As an example, off-axial Gregory telescope embodiment is used for infrared waveband region, due to the fact that, unlike the Cassegrain telescope, it provides a real exit pupil, and usage of the mirror corrector brings several advantages. Firstly, this feature may be used to include cold stop or adaptive mirror in the exit pupil, wherein corrector is introduced into a converging beam before the focus of the first mirror. Secondly, when placing corrector in the exit pupil of the optical system it is possible to eliminate high and low order aberrations of center point, which in turn improves optical system f-number, and minimize field aberrations. As another example, off-axial Ritchey-Chretien telescope embodiment is used as a good fit for visible region systems. Analysis and calculation results of optical systems with free-form correctors with surfaces, defined by Power polynomial series are presented in this paper. Advantages of different freeform surfaces usage depends on optical system layouts specifics.

Wavefront Coding (WFC) systems make use of an aspheric Phase-Mask (PM) and digital image processing to extend the Depth of Field (EDoF) of computational imaging systems. For years, several kinds of PM have been designed to produce a point spread function (PSF) near defocus-invariant. In this paper, the optimization of the phase deviation parameter is done by means of genetic algorithms (GAs). In this, the merit function minimizes the mean square error (MSE) between the diffraction limited Modulated Transfer Function (MTF) and the MTF of the system that is wavefront coded with different misfocus. WFC systems were simulated using the cubic, trefoil, and 4 Zernike polynomials phase-masks. Numerical results show defocus invariance aberration in all cases. Nevertheless, the best results are obtained by using the trefoil phase-mask, because the decoded image is almost free of artifacts.

The most widely used objectives for the space optics are mirror and catadioptric systems. We have considered several scheme types including the three-mirror schemes both of the Korsch-type and the systems without an intermediate image and compare them from the point of view of packaging conditions, image quality and achievable characteristics. The two-mirror systems with lens correctors are also analyzed. The optical layout and parameters of several variants are presented and the image quality is shown.

The minimum resolvable temperature difference (MRTD) and minimum detectable temperature difference (MDTD) are widely accepted static performance test parameters that best describe the field performance of thermal imaging systems. MRTD test is measured by determining the minimum temperature difference between the 4-bar target and the background required to resolve the thermal image of the bars by an observer. On the other hand, MDTD test is measured by determining the minimum temperature difference between the target and the background, which is required to detect the target from the thermal image. Different temperature differences between the target and the background with different target spatial dimensions were used while conducting both MRTD and MDTD measurements using collimator test systems. In this study, to evaluate the field performance of various thermal imaging systems, MRTD and MDTD tests were applied. Then, infrared simulations of pinhole and 4-bar collimator static test system targets were described based on the electro-optical parameters of unit under test (UUT) including detector resolution, system SiTF (Signal Transfer Function), system MTF (Modulation Transfer Function) and total optical transmission. With these inputs, the infrared simulation images of pinhole and 4-bar targets, which have adjustable temperature difference and different spatial frequency, were obtained in MATLAB environment. Then, the infrared simulations of pinhole and 4-bar target images were verified with thermal imaging system.

In this study, a mask suitable for three materials evaporated from one single e-beam source is developed to obtain uniform thickness distribution. The design method is based on film thickness theory and the assumption that a substrate holder rotates about its central axis during the deposition of films. The uniform thickness distributions of the SiO2, TiO2 and Ag films deposited with the designed mask are achieved in an e-beam evaporation chamber. The design of a mask in thickness uniformity for three coating materials cuts the development time and requires less trial and error than traditionally experimental correction loops.

The work associates with the catadioptric systems with two-component afocal achromatic compensator. The most catadioptric systems with afocal compensator have the power mirror part and the correctional lens part. The correctional lens part can be in parallel, in convergent beam or in both. One of the problems of such systems design is the thermal defocus by reason of the thermal aberration and the housing thermal expansion. We introduce the technique of thermal defocus compensation by choosing the optical material of the afocal compensator components. The components should be made from the optical materials with thermo-optical characteristics so after temperature changing the compensator should become non-afocal with the optical power enough to compensate the image plane thermal shift. Abbe numbers of the components should also have certain values for correction chromatic aberrations that reduces essentially the applicable optical materials quantity. The catalogues of the most vendors of optical materials in visible spectral range are studied for the purpose of finding the suitable couples for the technique. As a result, the advantages and possibilities of the plastic materials application in combination with optical glasses are shown. The examples of the optical design are given.

The interesting experiments for investigation of image formation in optical microscopes have been done by E. Abbe, A. Porter and L. Mandelshtam. These experiments have become the classical ones and they are widely used for explanation of Fourier optics. The principal disadvantage of them is difference in optical schemes for observation of object images and their spatial spectrums. The proposed optical setup makes possible demonstration of two stages of image formation – obtaining a spatial spectrum and composing a magnified object image – together in one plane. This setup contains two imaging channels separated by a beam splitter after a microscope objective. The first one forms a magnified object image, the second one – an image of a spatial spectrum. These images may be observed on a screen, via eyepieces or using image sensors. Any occluding of spectrum zones becomes visible and it leads to the corresponded changes in an object image. This optical setup would be useful for optical education and research.

The basis of this work is a modification of the modern design of surgical binoculars based on substitution of mineral glasses with polymer lenses. Aberration analyses of the proposed systems is shown.

Measuring large curvature radii of convex surfaces with high precision is a challenge because the spherometer’s focus must be positioned at the apex of the surface and at the center of curvature of the surface by moving the surface or the spherometer. If the radius of curvature is larger than the back focus of spherometer, then measurement is not possible. In this work, we propose to use the FOCOIVA system1 to move the focus of the spherometer in longitudinal way without modifying the f number by moving two lenses inside it, with this mechanism it is possible to measure radii of curvature of several meters in length. The curves of movement of the lenses and the optical parameters of the lenses that compose the spherometer are presented.

Inhomogeneous or gradient index media exhibit a refractive index varying with the position. This kind of media are very interesting because they can be found in both synthetic as well as real life optical devices such as the human lens. In this work we present the development of a computational tool for ray tracing in refractive optical systems. Particularly, the human eye is used as the optical system under study. An inhomogeneous medium with similar characteristics to the human lens is introduced and modeled by the so-called slices method. The useful of our proposal is illustrated by several graphical results.