Fifty years ago, Robert L. Powell and I discovered holographic interferometry while working at the Radar Laboratory of the University of Michigan’s Institute of Science and Technology. I have worked in this field for this entire time span, watched it grow from an unexplored technology to become a widespread industrial testing method, and I have contributed to these developments. In this paper, I will trace my history in this field from our discovery to my involvement in its theory and applications. I will conclude with a discussion of digital holography, which is currently replacing photographic holography for most research and industrial applications.

The subaperture and conformal nature of the MRF® polishing tool has proven its unmatched production capability and efficiency for more than a decade at leading optics manufacturers worldwide. The introduction of the third generation of manufacturing systems combined with newly developed MRF fluids pushes the limits of the technology to extend its benefits to very low roughness surfaces and high-precision freeform surfaces. In this article, after reviewing the benefits of the new platforms, two specific examples of very advanced capability will be discussed:

- A new super-fine MRF polishing fluid that is able to meet both form and roughness specifications for very demanding optics required for EUV applications and high power laser systems.

EUV optics, made of calcium fluoride or similar materials, ideally require sub-Angstrom surface roughness while achieving nm level form error. To achieve the above specifications, optics must undergo iterative global and local polishing processes. The new MRF polishing fluid minimizes the number of steps required if MRF® is used as the final step, or a reduction in the post-processing if a final smoothing step is performed.

- The total manufacturing process, including generation, pre-polishing, MRF and metrology, of a very steep freeform surface, highlighting the capabilities available in today’s optical fabrication companies.

Non-rotationally symmetric surfaces pose challenges to optical fabrication, mostly in the areas of polishing and metrology. The varying curvature of freeform surfaces drives the need for smaller, more “conformal” tools for polishing and reference beams for interferometry. In this paper, we present the fabrication results of a high-precision freeform surface.

Ion beam and plasma jet based techniques can be used in alternative machining processes for generating and finishing of ultra-precision optical surfaces. Since atomistic mechanisms are responsible for surface material modification, etching, and deposition, very high accuracy on the atomic level can be achieved. Various advanced techniques like pulse-width modulated ion beam figuring, sub-aperture reactive ion beam etching, or ion beam assisted structuring, planarization and smoothing technologies have been investigated aiming at precision on sub-nanometer height scale and lateral scales ranging over the full spatial wavelength range from nanometers to meters. Additionally, different atmospheric reactive plasma jet processes and plasma jet assisted process chains for generating, correction and smoothing of complex shaped optical surfaces like aspheres with large departures to best fit sphere or free forms exhibiting strong gradients have been developed in the last decade. In the paper an overview to the most recent trends of non-conventional ultra-precision optics processing is given and latest results of optics manufacturing are shown. Specific examples are given to demonstrate that form generation (e.g. for laser beam shaping optics) and surface finishing and polishing using atmospheric plasma jet tools are promising applications exhibiting advantages with respect to process efficiency and flexibility. Furthermore, the capabilities of ion beam surface figure correction using a new approach to control the tool function are demonstrated.

The Dielectric Total Internal Reflecting Concentrator (DTIRC) is a type of non-imaging optic that has been used in the past to increase the collection efficiency of photovoltaic (PV) cells and photodetectors. It does this by redirecting energy impinging on its largest aperture to a smaller aperture to which the absorber is attached. This paper explores the use of non-imaging optics for light emission control when combined with a Light Emitting Diode (LED). In this case, the smallest aperture of the concentrator acts as its input and the largest aperture as the output. This allows control of the angular characteristics of the emitted light beam and an increase of the illuminance at the target plane, which is of particular relevance in applications such as illumination and optical wireless communications. Its compact size and design characteristics make the DTIRC a more desirable geometry compared to other non-imaging optics when used as a first or secondary optic to control the emission characteristics of a light source. This paper reports the correlation between simulation and experimental results that validate the ability of DTIRCs to collimate the output beam of extended light sources.

Free form surfaces are now commonly used components in optics applications and can be widely found in fields such as ophthalmics, car illumination and head-up display systems and laser optics. The machining of free form optics on a 3-axis diamond turning machines is made possible with the use of tool servo machining which synchronises either or both the axial and radial motions of the tool and surface positions (X and Z axes) to the angular position of the spindle (C axis).

However, the machining of surfaces with non-zero gradient at the surface centre is particularly troublesome because the tool is still subject to a relatively large amplitude motion when reaching the central area of the surface. As a result, a small tool offset in either X (radial) or Y (height) creates a particular central signature that can be readily identified, measured and subsequently corrected by the machine operator.

In this paper, we report on a method to optimise the tool offset (X axis) in the particular case of non-zero central gradient and illustrate our discussion with simulation and measurement results.

This paper deals with thin films of Hematite (Fe₂O₃) deposited by ion beam assisted deposition (IBAD). It describes variation of optical properties with deposition parameters, especially oxygen flow and deposition rate. Optimal deposition parameters for Fe₂O₃ thin film were identified with criterion of the highest possible refractive index and lowest absorption. Film properties were measured and modelled by spectroscopic ellipsometry. Design of Fabry-Perot interference filter was used as a case study to compare properties of a Fe₂O₃ and TiO₂ as a high refractive index materials. The first design uses combination of TiO₂ and SiO₂ layers, which is considered as a standard solution. The second design consists of Fe₂O₃ and YF₃ layers. Comparison of these two designs shows that the design with SiO₂ and Fe₂O₃ has considerably lower layer count. Due to the fact that Fe₂O₃ has significant absorption in the visible spectra its use is limited to red and infrared wavelengths. The paper describes deposition of designed filter (Fe₂O₃ and YF₃) and measurement of its properties. Measured data are compared with the design.

In this work, the etch rate of silicon carbide and aluminum oxide were studied as a function of the angle etching material and flow of plasma. Al₂O₃ and SiC are important materials in the design of optical and electronic devices and the topography of the wafers has a large influence on the device quality. Argon was applied for the dry etching of Al₂O₃ and SiC wafers. The wafer slope for highest obtained etch is defined. Atomic force microscopy was used to good morphology control of etched wafers. Statistical and correlation analysis was applied to estimate the surface perfection. Interferometry allowed to control etching rate.

The colors of some living organisms assosiated with the surface structure. Irridesence butterfly wings is an example of such coloration. Optical effects such as interference, diffraction, polarization are responsible for physical colors appearance. Alongside with amazing beauty this structure represent interest for design of optical devices. Here we report the results of morphology investigation by atomic force microscopy. The difference in surface structure of black and blue wings areas is clearly observed. It explains the angle dependence of the wing blue color, since these micrometer and sub-micrometer quasiperiodical structures could control the light propagation, absorption and reflection.

This article describes method of measurement mechanical properties of carbon fiber composites in space. New material structures are specifically designed for use on space satellites. Composite structures will be exposed to cosmic radiation in Earth orbit on board of a '2U CubeSat' satellite. Piezoelectric ceramic sensors are used for detection mechanical vibrations of composite test strip. A great deal of attention is paid to signal processing using 8-bit microcontroler. Fast Fourier Transformation is used. Fundamental harmonic frequencies and damping from on-board measurements will serve as the input data for terrestrial data processing. The other step of elaboration data is creation of the physical model for evaluating mechanical properties of Carbon composite - Piezoelectric ceramic system. Evaluation of anisotropic mechanical properties of piezoelectric ceramics is an interesting secondary outcome of the investigation. Extreme changes in temperature and the effect of cosmic rays will affect the mechanical properties and durability of the material used for the external construction of satellites. Comparative terrestrial measurements will be performed.

High selectivity of surface-plasmon polaritons on wavelength can be used for reconstruction of color holograms illuminated with white light. In such a case, a combination of plasmonic filter and holographic microstructure is used. Compared to other techniques for creating holograms for white light reconstruction, such as rainbow holograms, the plasmonic approach offers full angle color reconstruction.

The plasmonic structure consists of a holographic grating recorded in a photo-resist material and a thin metallic layer on top of the grating. The parameters of both components are tuned to transmit only a selected spectral range when illuminated with white light. For RGB reconstruction three independent structures can be combined on a single substrate.

An excitation of plasmonic effects usually requires a relatively complicated setup containing prisms for in-coupling of optical waves. In this paper, a modification of the plasmonic hologram is proposed, which consists of two gratings recorded on opposite surfaces of a substrate. The first grating serves as an in-coupling element which also partially tunes the spectral transmittance of the structure. The second grating is metallized and out-couples the energy stored in the surface plasmon to a transmitted wave.

However, there is still a problem of diffraction efficiency of such transmission holographic structures. In order to optimize the transmittance and spectral selectivity, numerical simulations of light propagation through the plasmonic structure have been performed using MEEP software. The dependencies of transmitted light on various parameters of the diffraction gratings and metallic layer are discussed in detail.

Realistic reproduction of appearance of real-world materials by means of computer graphics requires accurate measurement and reconstruction of surface reflectance properties. We propose an interactive software simulation tool for modeling properties of a kaleidoscopic optical system for surface reflectance measurement. We use ray tracing to obtain fine grain simulation results corresponding to the resolution of a simulated image sensor and computing the reflections inside this system based on planar mirrors. We allow for a simulation of different geometric configurations of a kaleidoscope such as the number of mirrors, the length, and the taper angle. For accelerating the computation and delivering interactivity we use parallel processing of large groups of rays. Apart from the interactive mode our tool also features batch optimization suitable for automatic search for optimized kaleidoscope designs. We discuss the possibilities of the simulation and present some preliminary results obtained by using it in practice.

We report on an evaluation of the influence that fast changes of the refractive index has on the uncertainty of interferometric displacement measurement. Measurement of position within a limited range is typical for coordinate measuring systems such as nanometrology standards combining scanning probe microscopy (SPM) with precise positioning. For long-range systems the varying refractive index of air contributes the most to the overall uncertainty. We proposed to extend the principle of compensation of the fluctuations of the refractive index of air through monitoring the optical length within the measuring range of the displacement measuring interferometer. In this contribution we evaluate the level of uncertainty associated with the nature of the fluctuations of the refractive index of air in laser interferometry. We have observed that its fast variations, seen as length noise, are not linearly proportional to the measuring beam path but play a significant role only over distances longer than 50 mm. Over longer distances the length noise rises proportionally. The measurements were performed under conditions typical for metrology SPM systems.

The liquid variable focus lenses and mirrors are extensively studied for its variety of applications nowadays because it presents one of the simplest ways for applications as varying optical elements. Instead of other principles the liquid lenses and mirrors can be easily operated by changing the pressure pushing the liquid in and out of the base to change its surface curvature. In case of small diameter optical elements the surface curvature is given by its aperture diameter, applied pressure, and surface tension of the liquid. This feature enables to use such a variable optical element for fine surface tension measurement of small volume of the liquid sample, when the optical element, diameter, and pressure are measured. We are focused on surface tension measurement of small sample of liquid water under supercooled conditions by use of pressure measurement and optical identification of free liquid meniscus planarity. We developed a measurement stand with planar meniscus shape determination by its confocal visualization. We tried different light sources for 0.3 mm diameter meniscus illumination. We discuss an influence of the light source on the liquid meniscus optical element planarity measurement.

Optical frequency references for laser standards based on molecular iodine absorption cells represent one of the most used tool for frequency stabilization of lasers operating in a visible spectral range. In the industry oriented laser measurements and similar laser interferometry applications performed at atmospheric conditions, a refractive index of air plays a role of main uncertainty contributor. In these cases there is no need to use technologically complicated and expensive iodine references made of pure fused silica with precise pressure control of absorpbing media. A set of iodine cells made of borosilicate glass was filled with certain amount of absorbing media to define the saturation point of iodine inside. A combination of these two approaches (pyrex material and controlled saturation pressure of iodine) allows us to simplify the laser stabilization setup (there is no need of additional iodine pressure level control) and reduce the overall reference’s costs with ensuring of sufficient frequency stability of the system at the same time. Spectral properties of manufactured cells were tested by hyperfine transitions linewidth measurement and comparison with results from traditional fused silica cells was done to investigate the long-term iodine purity inside the references. As the transitions linewidth method shows a very high sensitivity to iodine purity level, this method is proposed to be an alternative approach in investigation of contamination in iodine absorption cells where traditionally used techniques - laser induced fluorescence (LIF) and absolute frequency shifts measurement - can not be used.

A spatial light modulator (SLM) is a versatile device capable of real-time generation of diffractive phase gratings. Employing the SLM in an optical setup opens the possibility of dynamic modification of properties of the incident laser beam, such as its splitting into an arbitrary number of diffracted beams, changing its convergence or its modification into non-traditional laser beam profiles. Advanced feedback procedures enable resolving complex phase masks correcting aberrations inherent to the whole optical system, such as imprecisions of manufacturing process, inhomogeneity of refractive index of materials used or misalignment of optical elements. In this work, generation of Bessel beams (BB) using the SLM is presented. The BB quality is very sensitive to the optical aberrations of the system, especially when higher topological charge is applied to create so-called optical vortices. Therefore, the method compensating those aberrations is applied and the corrected beam is inspected by a CCD camera and optical micro-manipulations of micro-particles. Our experimental results demonstrate successful trapping, rotation and translation of micrometer-sized particles purely by optical forces.

Here we present the results obtained by TR PIV measurements focused on detailed flow analysis in the selected region. The investigated area was placed 3mm above the blades axis and 5mm far from the blade edge. The captured images were firstly analysed on the mean velocity distribution and the intensity of turbulence {UV} statistics. Here we used the time resolved technique for the experimental study of the flow field in the agitated vessel. The results of the application POD and ODP algorithm on the captured datasets uncovered the existence of unsteady structures in the area that was assumed to be stable. The existence of these structures is bringing a novel view on the mixing process.

This paper describes optical scattering properties of muscle t issue, special traits, and the difficulties its composition causes. The pH of tissue and angle of the myofibrils relative to the incident light used as a probe changes the results of measurements. Distribution of colagen, as well as other substances that can be found in muscle tissue, also affect the outcome of any attempt to examine the sample via the means of optical analysis. Measurement results and scattering models are compared in effectiveness of characterization of the non-linear optical system that is muscle tissue for both medical use and food quality control, depending on the properties and composition of the tested sample.

The contribution reports the experimental results of preparation of thin metal films (nickel, aluminum) with low surface roughness using high-current impulse magnetron discharge plasma. The coatings were deposited on silica and silicon surfaces. It was found that by applying a certain negative bias voltage to the substrate, one can stimulate the smoothing of the surface topology. For the case of nickel deposition the average surface roughness decreased from about 8 nm to about 2 nm. The discussion of experimental data acquired under different deposition conditions is presented. The results allow us to single out the main factors influencing the surface roughness of the films and to suggest an analytical condition for smoothing process.

In this article we present the developed three-coordinate laser heterodyne interferometer that can be integrated in the commercially available industrial scanning probe and electron microscopes. It allows one to ensure traceability of measurements in nanometer range to the primary standard of meter. As outcome, the regular calibration of scanners becomes unnecessary, while the reproducibility and accuracy of the measurements dramatically increases.

Large aperture composite adaptive optics for laser applications is investigated in cooperation of Institute of Plasma Physic, Department of Instrumentation and Control Engineering FME CTU and 5M Ltd. We are exploring opportunity of a large-size high-power-laser deformable-mirror production using a lightweight bimorph actuated structure with a composite core. In order to produce a sufficiently large operational free aperture we are developing new technologies for production of flexible core, bimorph actuator and deformable mirror reflector. Full simulation of a deformable-mirrors structure was prepared and validated by complex testing. A deformable mirror actuation and a response of a complicated structure are investigated for an accurate control of the adaptive optics. An original adaptive optics control system and a bimorph deformable mirror driver were developed. Tests of material samples, components and sub-assemblies were completed. A subscale 120 mm bimorph deformable mirror prototype was designed, fabricated and thoroughly tested. A large-size 300 mm composite-core bimorph deformable mirror was simulated and optimized, fabrication of a prototype is carried on. A measurement and testing facility is modified to accommodate large sizes optics.

This paper describes a differential quadrature interferometer capable of measuring the mass velocities in the range of 50-10000 m/s. It can be used to obtain experimental data on the durability and kinetic properties of different classes of materials under shock-wave loading.

The ELI Beamlines facility will house repetition rate high-power lasers with pulse durations down to 15 fs and over petawatt peak powers. Our research group participates in the construction of a cryogenically cooled Yb:YAG multi-slab amplifier; part of the L2 beamline. The system shall provide square, super-Gaussian beam with nearly 2 ns pulses with rectangular temporal profile and energy of up to 10 J at 10 Hz. The laser will provide pump beams for broadband OPCPA stages. The diagnostic system of the pump laser is critical for the correct performance analysis, stabilization feedback and mostly for the machine interlock system as damages of the expensive optical components can develop very fast with the 10 Hz repetition rate. The diagnostic system provides key laser parameters and characteristics in temporal, spectral and spatial domain. The paper describes testing of the setup for measurements of the final 10 J output. Its design is based on a combination of optical wedges and diffractive sampler to facilitate multiple diagnostics on a relatively small footprint. The laser diagnostics package covers measurements in spatial domain such as near-field, far-field, or wavefront analysis, further optical spectrum, pulse energy and temporal shape. In order to detect possible damage dark-field analysis was implemented as well. The final setup was modeled in optical design software (Radiant Zemax) to understand its behavior and later tested together with real-time LabVIEW code developed by our group as being part of the machine interlock system. The first results of the tests as well as detailed description of the diagnostics package design are presented.

A sensitive method for optical birefringence measurement is presented. To optimize the signal over the noise ratio, the polarization of the laser beam is modulated exceptionally with a high frequency electro-optical modulator. The specially developed optical apparatus exhibits high sensitivity and accuracy, which were checked by measuring the Cotton-Mouton effect in nitrogen as a function of the pressure. It is able to measure the retardance down to 2x10^-4 rad. This apparatus will be used with the locked optical cavity. The optical cavity will serve as an optical path multiplier for increasing the sensitivity. This proposed set-up will be able to measure the Cotton-Mouton effect in helium, where the birefringence effect is Δn ≈ 2.4x10^-16.

We report on the results of the common collaborative project of applied research where the Institute of Scientific Instruments (ISI) of the Academy of Sciences of the Czech Republic and a company Meopta - optika joined their effort in development of high-precision interferometric systems for dimensional metrology and nanometrology. This research exploits previous results in the field of laser standards of optical frequencies and the methodology of interferometric metrology of length together with detection systems of interference signals and their processing at the ISI and the production technology of precise optical components at Meopta – optika.

The main aim of the project is a design of a complex interferometric measuring system in a form of a prototype serving as a master for further production. It concept is a modular family of components configurable for various arrangements primarily for multi-axis measurements in nanotechnology and surface inspection. Within this project we developed a compact, solid-state frequency stabilized laser referenced to iodine transitions and technology of iodine cells for laser frequency stabilization. A fundamental setup of the laser interferometer has been arranged and tested. The company Meopta – optika contributes with development of new technology together with a design of a machine for processing and polishing of high-precision flat-surface optical components.

The applicability of the digital holography to grinded surfaces shape measurements is experimentally examined with regard to the surface micro-roughness of brittle materials (optical glass). Multi-wavelength phase shifted digital holographic interferometry (holographic contouring) is used and its performance is analyzed. Holographic contouring is a great candidate for the precise shape measurement technique, which can be applied to the iterative manufacture process of optical elements. Optical surface artifacts with different radii of the spherical (convex and concave) shapes were prepared with different micro-roughness. Their optical surfaces were then holographically recorded using a designed setup. Two different measures were selected to estimate the quality of the holographic recording: first, the intensity profile of the reconstructed surface deviation as a consequence of the micro-roughness decrease, where the shape of the intensity profile develops as the surface is altering from strongly diffusive to almost specular; second, the correlation of the phase fields (surfaces shapes), which were holographically recorded using two light beams of different wavelengths. In this situation, the correlation function decreases with an increase in the noise amount in data. The presented preliminary results indicate that the multi- wavelength holographic contouring can be used for surface measurements of high-quality polished and nearly specular surfaces. On the other hand, the application of holographic contouring to polished surface measurement still represents a challenging task and remains unresolved even with the multidirection illumination.

The present work aims to analyze and characterize the macro-geometrical defects of surfaces.

As a way of characterization an optical method is used, which is the projection of fringes that is a technique of non-destructive measurement.

The location, depth and size of surface defects can be determined automatically by projection of four figures of rectilinear fringes shifted in phase on the surface to be tested. An optical mounting of triangulation to project the fringes is then performed.

After projection, the projected gratings images are captured by a CCD camera, digitized and stored in computer memory. The application of phase shifting algorithm with four steps is achieved to determine the initial phase that contains the "measurand", which is the difference in shape. Pieces with different forms were tested.

In this work we study the venom of two Centruroides scorpion species using Raman spectroscopy. The spectra analysis allows to determine the venoms chemical composition and to establish the main differences and similarities among the species. It is also shown that the use of Principal Component Analysis may help to tell apart between the scorpion species.

In recent times, resin bond grinding wheels have often been used for the precise grinding of aspheric surfaces. In this paper, the influence of changes in the circumferential speed of the resin bond grinding wheel on the microroughness of the produced surface and also on the volume of the structures and the scratches is presented. The article also discusses how the cutting wear of the tool affects the surface quality and shows the correlation between the circumferential speed and the rate of degradation of the resin bond grinding wheel. A circumferential speed interval from 12 m/s to 24 m/s was investigated and the effect of tool degradation was observed at 1.9-hour intervals. The results of the experiment show that the optimal circumferential speed of the tool lies around 20 m/s. At this speed, the tool produces a perfectly polishable surface and tool degradation is minimized.

We have realized an optical design of air space doublet of 100 mm clear aperture and 520 mm focal length that is optimized with respect to a quality of wavefront error better than 0.07 λ RMS for on-axis imaging at wavelengths of 633 nm and 450 nm. To minimize optical aberrations we have designed one of the four surfaces to be an aspherical. Based on a tolerance analyses those take into account planned spherical and aspherical technologies for surfaces realization and measurement equipment we have realized the doublet. In the paper there is described a technique of the optical design, tolerance analysis, technique of objective realization and results of the optical elements realization.

In this work, the theoretical study of macroscopic dielectric and optical properties of ferroelectric polydomain samples is presented. The role of average spontaneous polarization of the polydomain sample on the macroscopic dielectric response is analyzed. The measurement method of average spontaneous polarization using optical methods is suggested and analyzed. The presented analysis is focused on the computation of optical properties near ferroelectric domain walls. The computation of refractive index in the regions near neutral domain walls is presented. Since it is known that the refractive index depends on the configuration of the crystal lattice within a particular domain and on the internal and external electric fields, the obtained results will be used for a suggested method of 3D imaging of ferroelectric domain walls and internal electric fields using digital holographic interferometry.

The modern trend in high power laser applications such as welding, cutting and surface hardening lies in the use of solid-state lasers. The output beam of these lasers is characterized by a Gaussian intensity distribution. However, the laser beams with different intensity distributions, e.g. top-hat, are preferable in various applications. In this paper we present a new type of deformable mirror suitable for the corresponding laser beam shaping. The deformation of the mirror is achieved by an underlying array of actuators and a pressurized coolant that also provides the necessary cooling. We describe the results of the surface shape measurement using a 3D scanner for different settings of actuators. Further, we show the achieved intensity distributions measured by a beam profiler for a low power laser beam reflected from the mirror.

We are developing an Yb:YAG thin disk regenerative amplifier operating at 1 kHz repetition rate which should deliver output of 100 W of average power which corresponds to the pulse energy of 100 mJ. In order to achieve such high output energy, large size mode matching on a thin-disk is required to avoid optical damage but on the other hand, larger mode area is more susceptible to the influence of optical phase distortions (OPD’s) thus limits achievable pulse energy and beam quality. We developed a compact setup allowing precise measurement of the thin-disk deformations by implementation of a Hartmann-Shack wavefront sensor and a single mode probe laser diode. In comparison to the interferometric measurement methods, our approach brings a number of advantages like simplicity of alignment, compactness and robustness, at the same time keeping the high precision of measurement in a range of few nanometers.

In this contribution we present a technology for thin film optical coating deposition and laser induced damage threshold (LIDT) testing of coatings available at the Institute of Scientific Instruments. We use our e-beam evaporation coating system equipped with plasma ion assisted deposition to produce various optical coatings and a LIDT test station to test them. The station allows for testing at room temperature as well as cryogenic conditions.

We report on the discovery of a new variable star during the search for new exoplanets in the Centaurus constellation from the archive of the FRAM telescope, operated by the FRAM team at Los Leones, near Malargüe, Argentina. The star is catalogued as GSC 08630-01117 (11h 36m 10s -53° 12’ 15.04”). From the light curve, the star should be an ELL-type variable. We computed the period P = 0.6311+/- 0.0002 days. The maximum is 13.07 +/- 0.02 mag and minimum is 13.22 +/-0.02 mag (in the Johnson V filter) with an amplitude of about 0.15 mag. We registered this star in the CzeV catalogue and in the VSX catalogue as new variable star CzeV603. The FRAM telescope observed several transits of known exoplanets. These observations show the ability to detect new exoplanets using the FRAM telescope.

The paper presents an analysis of deflection of a reference plate and a tested plane parallel plate due to gravity during measurement with the Fizeau interferometer. Detailed expressions for the calculation of a deflection assuming different supports are presented. Furthermore, the relations for the calculation of a minimum thickness of a reference plate of the interferometer ensuring the required accuracy of measurement are given as well.

This work describes and analyzes a method for an evaluation of interferometric testing of optical surfaces, which is based on evaluation of similarity between the interferogram of the tested surface and the virtual interferogram of the nominal surface. The evaluation process is described as an optimization problem and the correlation coefficient between both interferograms is used as a merit function. The performance of the method is presented on examples of testing optical surfaces.

This paper describes a quest to find simple technique to superpolish Zerodur asphere (55μm departure from best fit sphere) that could be employed on old fashion way 1-excenter optical polishing machine. The work focuses on selection of polishing technology, study of different polishing slurries and optimization of polishing setup. It is demonstrated that either by use of fine colloidal CeO2 slurry or by use of bowl-feed polishing setup with CeO2 charged pitch we could reach 0.4nm RMS roughness while removing <30nm of surface layer. This technique, although not optimized, was successfully used to improve surface roughness on already prepolished Zerodur aspheres without necessity to involve sophisticated super-polishing technology and highly trained manpower.

Chromatic distortion represents a limit parameter for many optical systems. For telescope objectives low chromatic aberration is especially important. The choice of appropriate materials is therefore crucial for the production of optical elements.

The S-FPL-53 glass produced by Ohara Corporation is a readily available material with low dispersion. Its high Abbe number indicates low achromatism, therefore it is used in all the above-mentioned designs to achieve good correction. On the other hand, this fluorite glass is quite soft and has a high thermal expansion coefficient, so it is really difficult to polish.

In this paper possible solutions to problems related to polishing aspherical lenses applying CNC technology and to polishing spherical lenses applying classical technology are discussed. By combining various conditions it is possible to achieve required roughness and shape of the lens surface.

Optical document security represents an important field of application of analogue and synthetic diffractive structures. Most of the security elements are based on visual effects formed by diffraction on a structure with the details in the order of hundreds of nanometers. However, to improve the anti-counterfeiting properties of these structures, various types of hidden features are included within the area of the security elements. They are not visible under normal lighting but it is possible to easily reveal the hidden information under specially-defined geometry and/or type of illumination.

In this paper, theory and application of a novel type of hidden diffractive security element are presented. It combines standard visual properties of synthetic holograms with waveguide effects. The hidden information is recorded using a special grating, which is not visible under normal observation geometry. The encoded image can be reconstructed only when the proper guided mode appears in a substrate. During the reconstruction, light is coupled into a waveguide (holographic foil) using a grating coupler and after traveling through the substrate in a chosen direction it is selectively out-coupled within the areas containing the hidden information. Several elements with different properties have been designed, fabricated and compared with theory. Principles of diffraction and waveguide effects, realization technology and properties of the realized test samples are presented.

The advantage of the combination of diffractive and waveguide effects is that the resulting hidden effect is sophisticated but easily readable with no additional tools.

Hyperspectral imaging as an instrument for obtaining a wide range of information on the world around us is a fast developing area of modern technology. In such systems, the desired information is obtained via the processing of stored spectral information of a measured scene. One of the main advantages of hyperspectral imaging over conventional imaging methods is the use of a broad spectral range, which is not restricted to just the visible range but can extend to adjacent regions and further, for example, deeply into the infrared region. The main element in such hyperspectral systems is the spectral separating system, which can be based on a wide variety of spectral dependent physical processes - birefringence, refraction, diffraction, etc. In this contribution, we would like to present the design and fabrication process of such a spectral separating system based on diffraction grating. The main requirements for this system were - operation in the long-wavelength infrared region (LWIR, 7-14 um), the highest possible diffraction efficiency in this spectral region with respect to the black body radiation of a temperature of 350 K, and the avoidance of restrictions inherent to fabrication. The design was carried out with the use of Scalar theory of transmission gratings, which is based on the idea of thin grating. The obtained results were compared to the designs produced via the Rigorous coupled wave theory (RCWA) and Finite Element Method (FEM). Fabrication of the designed grating was done in germanium with the use of single-point diamond turning.

The aim of this study was to determine the optimal subaperture polishing procedure for aspherical surfaces on the Optotech MCP 250 CNC machine. Due to the fact that the CNC subaperture polishing process runs along well defined paths, certain frequencies develop on the polished surface, which can be limiting for the resulting microroughness. A proper sequence of polishing steps in different tool motion control modes can minimize these frequencies and help to substantially reduce microroughness. In this context, various tool motion control modes ("Spiral spindle mode", "Spiral axis mode" and "Raster mode") in combination with different tools were tested. The resulting microroughness values were observed in the defined mid-frequency and high-frequency areas. The best results, i.e. the lowest microroughness values were obtained using a combination of the processes "Ball spiral axis mode", "FEM raster mode", "spiral spindle 2D FEM correction mode" and "AFJ spiral axis mode"

Metal and semiconductor nanoparticles have excellent optical and electrochemical properties that strongly depend on their size and shape. Local biosensors are advanced devices, whose basic working principle is to analyze spectra of noble metal nanoparticles. Here a model of a local biosensor is described. It takes into account the interaction of the particle with a glass prism and the viewing angle of lens. The results for the layered particle made of a polystyrene latex core with a golden outer shell and for nanorods are presented. The influence of the metal shell thickness, particle diameter and the nanoscale rod form on the location of dissipation spectrum maximum is analyzed.

Paper presents the method for shape measurement by digital holography based on wavelength contouring. The method employs multiple measurements from different illumination directions followed by stitching of the individual measurements by least square method. This approach is promising in measuring of steeper surface slopes more accurately

A measurement system to monitor the turning tool achieves a reduction in production rejects by decreasing the delay time between tool wear detection and quality control of the surface, which usually takes place after the time-intensive polishing process. In highly automated production of lucent synthetic lenses the standardized polishing process turns out to be inefficient if there is an insufficient surface quality caused by outrunning tool wear limits of the undergone turning process. The possibility to indicate the tool’s wear will be demonstrated by checking the surface characteristics of synthetic lenses. For that research an experimental measurement setup is shown. This optical measurement system detects the surface’s roughness, which is indicative of tool wear.

Modified folded Jamin interferometer for on-line measurement of refractive index of gases was designed, constructed and tested. The accuracy of this interferometer is better than 10-6 and can be still approved about two orders by appropriate mathematical method. Interferometer is almost vibration insensitive with vibration noise equivalent to refractive index variation 2•10^-9. The interferometer qualities were tested by air refractive index monitoring.

The developed method is used for subsurface damage evaluation. It is based on CNC subaperture asymmetric polishing of the surface, which leads to the formation of a wedge with decreasing depth, depending on the diameter and a subsequent analysis of the surface using White - Light Interferometry. In the evaluation, 'negative PV value' method was used enabling the detection of the depth of damage with the accuracy of 1 micron.

The microstructure of transparent yttrium-aluminum garnet (YAG) ceramics is characterized using different microstructural descriptors, with special focus on grain size numbers. Both linear and planar grain size numbers are used to describe the dependence of the average grain size on Yb dopant content (0-10 at.%), sintering additive (tetraethyl orthosilicate, TEOS) content (0.3-0.5 wt.%) and firing time. Although the two grain size numbers are very close for the materials studied (with ratios very close to unity, around 0.987 ± 0.109), these two numbers are principally independent and provide complementary microstructural information. Their relations to other microstructural descriptors (interface density, mean curvature integral density, mean chord length, Jeffries size) are discussed throughout the text. It is found that Yb doping of more than 3 at.% has a grain-growth-inhibiting effect (after sufficiently long firing times), but differences in the TEOS content between 0.3 and 0.5 wt.% do not have any sensible effect. The largest effect on the microstructure is exerted by the firing time (with prolonged firing times leading to grain growth), but with higher Yb doping the effect of firing time on the grain size becomes less pronounced: for YAG samples without Yb doping, increasing the firing time by a factor of 8 (from 2 h to 16 h), deceases the grain size number by 33.2-35.0 %, whereas with a Yb dopant content of 10 at.%, the corresponding decrease in the grain size number is only 8.7-10.0 %. These findings are fully corroborated using the other microstructural descriptors.

Affordable, long-wave infrared hyperspectral imaging calls for use of an uncooled FPA with high-throughput optics. This paper describes the design of the optical part of a stationary hyperspectral imager in a spectral range of 7–14 um with a field of view of 20°×10°. The imager employs a push-broom method made by a scanning mirror. High throughput and a demand for simplicity and rigidity led to a fully refractive design with highly aspheric surfaces and off-axis positioning of the detector array. The design was optimized to exploit the machinability of infrared materials by the SPDT method and a simple assemblage.

Laser induced damage threshold is a key component characteristic while building high-performance laser system, establishing maximum achievable energy and consequently average power of the laser. Reliable and stable laser sources are desirable both in academic and industrial areas. To assure these quality criteria, involved components have to be tested and proved at certain values. The goal of HiLASE project is to develop and provide such highly progressive laser systems, and consequently advance in related areas, as high-energy laser components. Together with laser system is developed LIDT station to provide necessary background for components reliability and later application potential for final beamlines. Such station, however, has to meet certain criteria as well, to ensure reliability of conducted measurements and credibility of obtained results. ISO 21254 standard series describes methods of damage detection and principles of ensuring reliability of damage threshold measurement. Nevertheless, unique nature of HiLASE lasers allows new approach, which makes design of proper measuring station state-of-the-art challenge. Following paper reports recent progress in design of laser induced damage threshold station developed within HiLASE project.

The presented paper shows results and a comparison of FEM numerical simulations and optical tests of the assembly of a precise Zerodur mirror with a mounting structure for space applications. It also shows how the curing of adhesive film can impact the optical surface, especially as regards deformations. Finally, the paper shows the results of the figure quality analysis, which are based on data from FEM simulation of optical surface deformations.

Thermally-induced deformations of steering mirrors reflecting 100 J/10 Hz laser pulses in vacuum have been analyzed. This deformation is caused by the thermal stress arisen due to parasitic absorption of 1 kW square-shaped flat-top laser beam in the dielectric multi-layer structure. Deformation depends on amount of absorbed power and geometry of the mirror as well as on the heat removal scheme. In our calculations, the following percentages of absorption of the incident power have been used: 1%, 0.5% and 0.1%. The absorbed power has been considered to be much higher than that expected in reality to assess the worst case scenario. Rectangular and circular mirrors made of zerodur (low thermal expansion glass) were considered for these simulations. The effect of coating layers on induced deformations has been neglected. Induced deformation of the mirror surface can significantly degrade the quality of the laser beam in the beam delivery system. Therefore, the proper design of the cooling scheme for the mirror in order to minimize the deformations is needed. Three possible cooling schemes of the mirror have been investigated. The first one takes advantage of a radiation cooling of the mirror and a copper heatsink fixed to the rear face of the mirror, the second scheme is based on additional heat conduction provided by flexible copper wires connected to the mirror holder, and the last scheme combines two above mentioned methods.

In this contribution, we would like to present our results and discussions of the impact of overmodulation on spectral sensitivity in high efficient transmission gratings. The theoretical aspect of this issue was examined through Kogelnik’s coupled wave theory and RCWA. Experimentally, we measured the spectral response of volume phase gratings produced in the Bayfol HX photopolymer and compared it with the theory. It was found that the spectral response has a character similar to angular sensitivity with respect to overmodulation apart from the pronounced wavelength-dependent spectral asymmetry.

Photopolymer recording systems have received a great deal of attention as a material for optical information storage and production of diffraction gratings. Before using these materials in such systems, it is important to characterize them and understand the processes which run during holographic recording, so that the recording itself can be optimized to obtain an efficient diffraction grating. In this contribution, we present a new method for real-time measurement of the diffraction response of reflection gratings during the recording process. Usually, the recording process in photopolymers is characterized by the real-time measurement of a transmission diffraction grating growth. This method does not allow measuring the growth of gratings with a very narrow spatial period in the reflection configuration. The new approach is based on the idea that the reflection grating is illuminated with white light at a different angle from the recording one and the diffraction efficiency is continuously measured with a spectrophotometer. Kogelnik’s coupled wave theory is used as the theoretical background in this contribution. Experimentally, the photopolymer Bayfol HX has been tested in the reflection configuration and growth curves have been measured to show a good applicability of the detection method.

All-dielectric grating with more than 98% efficiency over the reflective band of 40 nm with the central wavelength at 1053 nm is simulated for the angle of incidence 72 degrees. For the grating design we used the fact that chirped mirrors give wider reflective band than usual quarter-wavelength dielectric mirrors. Grating grooves and the very first layer under the grooves in our model is made of fused silica; underneath of the top layer we placed a chirped stack of 13 HfO₂/SiO₂ layers. Tolerances for groove depth and angle of incidence are estimated, optimal duty-cycle parameter is found out. Electric field distribution inside of the grating is also numerically studied. The model is simulated by two methods: numerical Fourier Modal Method in LightTrans Virtual Lab and semi-analytical Volume Integral Equation Method. The results obtained by both methods show excellent agreement.

Recently, multi-layer surface profiling and inspection has been considered an emerging topic that can be used to solve various manufacturing inspection problems, such as graded index lenses, TSV (Thru-Silicon Via), and optical coating. In our study, we proposed a gated wavefront sensing approach to estimate the multi-layer surface profile. In this paper, we set up an experimental platform to validate our theoretical models and methods. Our test bed consists of pulse laser, collimator, prism, well-defined focusing lens, testing specimen, and gated wavefront sensing assembly (e.g., lenslet and gated camera). Typical wavefront measurement steps are carried out for the gated system, except the reflectance is timed against its time of flight as well as its intensity profile. By synchronizing the laser pulses to the camera gate time, it is possible to discriminate a multi-layer wavefront from its neighbouring discrete layer reflections.