This PDF file contains the front matter associated with SPIE Proceedings Volume 9579 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

My research focuses on the use of computation/algorithms to create new optical microscopy, sensing, and diagnostic techniques, significantly improving existing tools for probing micro- and nano-objects while also simplifying the designs of these analysis tools. In this presentation, I will introduce a new set of computational microscopes which use lens-free on-chip imaging to replace traditional lenses with holographic reconstruction algorithms. Basically, 3D images of specimens are reconstructed from their "shadows" providing considerably improved field-of-view (FOV) and depth-of-field, thus enabling large sample volumes to be rapidly imaged, even at nanoscale. These new computational microscopes routinely generate >1–2 billion pixels (giga-pixels), where even single viruses can be detected with a FOV that is >100 fold wider than other techniques. At the heart of this leapfrog performance lie self-assembled liquid nano-lenses that are computationally imaged on a chip. These self-assembled nano-lenses are stable for >1 hour at room temperature, and are composed of a biocompatible buffer that prevents nano-particle aggregation while also acting as a spatial "phase mask." The field-of-view of these computational microscopes is equal to the active-area of the sensor-array, easily reaching, for example, >20 mm² or >10 cm² by employing state-of- the-art CMOS or CCD imaging chips, respectively.

In addition to this remarkable increase in throughput, another major benefit of this technology is that it lends itself to field-portable and cost-effective designs which easily integrate with smartphones to conduct giga-pixel telepathology and microscopy even in resource-poor and remote settings where traditional techniques are difficult to implement and sustain, thus opening the door to various telemedicine applications in global health. Some other examples of these smartphone-based biomedical tools that I will describe include imaging flow cytometers, immunochromatographic diagnostic test readers, bacteria/pathogen sensors, blood analyzers for complete blood count, and allergen detectors. Through the development of similar computational imagers, I will also report the discovery of new 3D swimming patterns observed in human and animal sperm. One of this newly discovered and extremely rare motion is in the form of "chiral ribbons" where the planar swings of the sperm head occur on an osculating plane creating in some cases a helical ribbon and in some others a twisted ribbon. Shedding light onto the statistics and biophysics of various micro-swimmers' 3D motion, these results provide an important example of how biomedical imaging significantly benefits from emerging computational algorithms/theories, revolutionizing existing tools for observing various micro- and nano-scale phenomena in innovative, high-throughput, and yet cost-effective ways.

Three years ago, industry and consumers learned that there was more to Head Mounted Displays (HMDs) than the long-lasting but steady market for defense or the market for gadget video player headsets: the first versions of Smart Glasses were introduced to the public. Since then, most major consumer electronics companies unveiled their own versions of Connected Glasses, Smart Glasses or Smart Eyewear, AR (Augmented Reality) and VR (Virtual Reality) headsets. This rush resulted in the build-up of a formidable zoo of optical technologies, each claiming to be best suited for the task on hand. Today, the question is not so much anymore "will the Smart Glass market happen?" but rather "which optical technologies will be best fitted for the various declinations of the existing wearable display market," one of the main declination being the Smart Glasses market.

Multi-photon degenerate four-wave mixing is demonstrated as an ultrasensitive absorption-based optical method for detection, separation and identification of biomarker proteins in the development of early diagnostic methods for HIV- 1, cancer and neurodegenerative diseases using compact, portable microarrays and capillary- or microchip-based chemical separation systems that offer high chemical specificity levels. The wave-mixing signal has a quadratic dependence on concentration, and hence, it allows more reliable monitoring of smaller changes in analyte properties. Our wave-mixing detection sensitivity is comparable or better than those of current methods including enzyme-linked immunoassay for clinical diagnostic and screening. Detection sensitivity is excellent since the wave-mixing signal is a coherent laser-like beam that can be collected with virtually 100% collection efficiency with high S/N. Our analysis time is short (1-15 minutes) for molecular weight-based protein separation as compared to that of a conventional separation technique, e.g., sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When ultrasensitive wavemixing detection is paired with high-resolution capillary- or microchip-based separation systems, biomarkers can be separated and identified at the zepto- and yocto-mole levels for a wide range of analytes. Specific analytes can be captured in a microchannel through the use of antibody-antigen interactions that provide better chemical specificity as compared to size-based separation alone. The technique can also be combined with immune-precipitation and a multichannel capillary array for high-throughput analysis of more complex protein samples. Wave mixing allows the use of chromophores and absorption-modifying tags, in addition to conventional fluorophores, for online detection of immunecomplexes related to cancer.

Ever since the first functional lasers were built about 50 years ago, researchers and doctors dream of a medical use for such systems. Today’s technology is finally advanced enough to realize these ambitions in a variety of medical fields. There are well-established laser based systems in ophthalmology, dental applications, treatment of kidney stones, and many more. Using lasers presents more than just an alternative to conventional methods for osteotomies. It offers less tissue damage, faster healing times, comparable intervention duration and in consequence improves postoperative treatment of patients. However, there are a few factors that limit routine applications. These technical drawbacks include missing depth control and safe guiding of the laser beam. This paper presents the engineering and integration of a miniaturized laser head for a computer assisted and robot-guided laser osteotome (CARLO®), which can overcome the mentioned drawbacks. The CARLO® device ensures a safe and precise guidance of the laser beam. Such guidance also enables new opportunities and methods, e.g. free geometrical functional cuts, which have the potential to revolutionize bone surgery. The laser head is optimized for beam shaping, target conditioning, working distance, compactness and the integration of all other parts needed, e.g. CCD-cameras for monitoring and referencing, a visible laser for cut simulation, etc. The beam coming out of the laser system is conditioned in shape, energy properties and working distance with an optical arrangement to achieve the desired cutting performance. Here also parameters like optical losses, operating mode, optics materials and long-term stability have are taken into account.

Safe drinking water is essential for human health, yet over a billion people worldwide do not have access to safe drinking water. Due to the presence and accumulation of biological contaminants in natural waters (e.g., pathogens and neuro-, hepato-, and cytotoxins associated with algal blooms) remain a critical challenge in the provision of safe drinking water globally. It is not financially feasible and practical to monitor and quantify water quality frequently enough to identify the potential health risk due to contamination, especially in developing countries. We propose a low-cost, small-profile multispectral (MS) system based on Digital Holographic Microscopy (DHM) and investigate methods for rapidly capturing holographic data of natural water samples. We have developed a test-bed for an MSDHM instrument to produce and capture holographic data of the sample at different wavelengths in the visible and the near Infra-red spectral region, allowing for resolution improvement in the reconstructed images. Additionally, we have developed high-speed statistical signal processing and analysis techniques to facilitate rapid reconstruction and assessment of the MS holographic data being captured by the MSDHM instrument. The proposed system is used to examine cyanobacteria as well as Cryptosporidium parvum oocysts which remain important and difficult to treat microbiological contaminants that must be addressed for the provision of safe drinking water globally.

Fluorescent imaging, often synonymous with microscopic imaging, is an imaging modality whereby various features of a target are observed based on assignment of chemical labels. These labels are in most cases indirect tracers of specific structures or chemical compounds which cannot be otherwise identified. The tracers are excited by an illuminating source and they in turn emit light at specific wavelengths. This light is then captured by an imaging device and represented as an indirect observation of the specific feature in the sample. The process of excitation and imaging of the emitted light is performed sequentially and is proportional to the number of tracers or fluorescence species present in the sample. We present an imaging system that can image fluorescent tracers, in the visible and the near Infra-red, simultaneously. This system is capable of illuminating the target with different excitation light sources and capture the corresponding fluorescence images in one snapshot using a series of mirrors to capture different views of the sample. The simultaneously captured image are fused using a computational reconstruction process to present a coherent multispectral fluorescence image. The system is proposed for use in applications where the rapid enumeration of fluorescent species in a large field of view is paramount as opposed to their microscopic image in a narrow field of view. The system was tested using a controlled cocktail solution of four different types fluorescent microspheres and was able to enumerate the microspheres based on their different fluorescent signatures as captured by the system.

Publisher's Note: This paper, originally published on 3 September, 2015, was withdrawn on 27th October, 2016, at the authors' request.

As line scanning short wave infrared (SWIR) hyperspectral imaging (HSI) is a growing field in the food industry, it is important to select efficient illumination designs to image contaminants with high contrast and low noise. Illumination systems can efficiently be compared and optimized through the use of ray tracing simulations. However, these simulations provide illumination patterns in absolute radiometric units while HSI systems typically provide relative measurements. To bridge this gap, a supercontinuum laser and monochromator setup was used in this study to calibrate a SWIR HSI imager in spectral radiometric units. For the radiometric calibration, an integrating sphere (IS) was illuminated with the monochromatic laser light, while both a high sensitivity photodiode and the hyperspectral camera were positioned at different ports of the IS to measure the diffuse light synchronously. For each spectral band, the radiance observed by the imager corresponding to a line was detected using image analysis, while the remainder of the image was used to sample the noise of the sensor. Laser power fluctuations were monitored using a power meter coupled with a thermal sensor, allowing for their correction. As these measurements were time consuming, while InGaAs based sensors are very sensitive to thermal drift, the dark current was sampled frequently to avoid noise time drifts. This approach allowed correcting for 6% of temporal noise fluctuations. A per-pixel linear radiometric model was fitted with an R² of 0:94±0:3 and used to transfer the measured light distribution of a halogen spot with and without a diffuser into absolute radiometric units. This allowed comparing measurements with the results of ray tracing.

OPTRA is currently developing a Risley Prism Universal Pointing System (RPUPS): a highly customizable cued beamsteering system. The RPUPS consists of a visible or infrared cueing imager co-aligned with an optical beam steering system’s pointing-field-of-regard. The cueing imager is used to identify a region-of-interest within its wide field-of-view, via a wireless tablet device. The tablet user can choose to manually or automatically, identify and track regions-of-interest. The optical beam steering system uses a matched pair of Risley Prisms to direct an interrogating optical system’s instantaneous-field-of-view onto the identified region-of-interest. The tablet updates the user with real time information from both the cueing imager and the interrogating optical system. Risley prism material and geometry choices provide operating wavelength, aperture size, and field-of-regard flexibility for this front-end pointing component. Back-end components may be receive-only, transmit-only, or transmit/receive combinations. The flexibility of the RPUPS allows for mission specific customization where applications include but are not limited to: synthetic foveated imaging, spectroscopic probes and laser (LIDAR) ranging and tracking. This paper will focus on the design and anticipated applications of the RPUPS.

In continuation of last year’s paper on the use of near field imaging, which basically is a reflective shadowgraph method, for characterization of glossy surfaces like printed matter or laminated material, further developments are discussed. Beside the identification of several types of surfaces and related features, for which the method is applicable, several refinements are introduced. The theory of the method is extended, based on a mixed Fourier optical and geometrical approach, leading to rules of thumb for the resolution to be expected, giving a framework for design. Further, a refined experimental set-up is introduced. Variation of plane of focus and incident angle are used for separation of various the images of he layers of the surface under test, cross and parallel polarization techniques are applied. Finally, exemplary measurement results and examples are included.

We have studied the object silhouettes and surface direction through the stereo matching image processing to recognize the position, size and surface direction of the object. For this study we construct the pixel number change distribution of the HSI color component level, the binary component level image by the standard deviation threshold, the 4 directional pixels connectivity filter, the surface elements correspondence by the stereo matching and the projection rule relation. We note that the HSI color component level change tendency of the object image near the focus position is more stable than the HSI color component level change tendency of the object image over the unfocused range. We use the HSI color component level images near the fine focused position to extract the object silhouette. We extract the object silhouette properly. We find the surface direction of the object by the pixel numbers of the correspondence surface areas and the projection cosine rule after the stereo matching image processing by the characteristic areas and the synthesized colors. The epipolar geometry is used in this study because a pair of imager is arranged on the same epipolar plane. The surface direction detection results in the proper angle calculation. The construction of the object silhouettes and the surface direction detection of the object are realized.

Transformation Optics (TO) provides the mathematical framework for representing the behavior of electromagnetic radiation in a given geometry by “transforming” it to an alternative, usually more desirable, geometry through an appropriate mapping of the constituent material parameters. Using a quasi-conformal mapping, the restrictions on the required material parameters can be relaxed allowing isotropic inhomogeneous all-dielectric materials to be employed. This approach has led to the development of a new and powerful design tool for gradient-index (GRIN) optical systems. Using TO, aspherical lenses can be transformed to simpler spherical and flat geometries or even rotationally-asymmetric shapes which result in true 3D GRIN profiles. TO can also potentially be extended to collapse an entire lens system into a representative GRIN profile thus reducing its physical dimensions while retaining the optical performance of the original system. However, dispersion effects of the constituent materials often limit the bandwidth of metamaterial and TO structures thus restricting their potential applicability. Nonetheless, with the proper pairing of GRIN profile and lens geometry to a given material system, chromatic aberrations can be minimized. To aid in the GRIN construction, we employ advanced multi-objective optimization algorithms which allow the designer to explicitly view the trade-offs between all design objectives such as RMS spot size, field-of-view (FOV), lens thickness, 𝛥𝑛, and focal drift due to chromatic aberrations. We present an overview of our TO-enabled GRIN lens design process and analysis techniques while demonstrating designs which minimize the presence of mono- and poly-chromatic aberrations and discuss their requisite material systems.

Simulated images provide insight into optical system performance. If the Point Spread Function (PSF) is assumed spatially invariant, then the simulated image is the convolution of the PSF with the object scene. If the PSF varies across the field, multiple field points are sampled and interpolated to give the PSF. Simulated images are then assembled from the individual PSFs. These techniques assume a 2D planar object. We extend the image simulations to 3D scenes. The PSF now depends on the field point location and distance in object space. We investigate 3D scene simulation and examine approximations that reduce computation time.

Monocentric lenses allow high resolution panoramic cameras, where imaging fiber bundles transport the hemispherical image surface to conventional focal planes. Refraction at the curved image surface limits the field of view coupled through a single bundle of straight fibers to less than ±34°, even for NA 1 fibers. Previously we have demonstrated a nearly continuous 128° field of view using a single lens and multiple adjacent straight fiber-coupled image sensors, but this imposes mechanical complexity of fiber bundle shaping and integration. However, a 3D waveguide structure with internally curved optical fiber pathways can couple the full continuous field of view onto a single focal plane. Here, we demonstrate wide-field imaging using a monocentric lens and a single curved fiber bundle, showing that the 3D bundle formed from a tapered fiber bundle can be used for relaying a 128° field of view from a curved input to the planar output face. We numerically show the coupling efficiency of light to the tapered bundle for different field of views depends on the taper ratio of the bundle as well as center of the curvature chosen for polishing of the fiber bundle facet. We characterize a tapered fiber bundle by measuring the angle dependent impulse response, transmission efficiency and the divergence angle of the light propagating from the output end of the fiber.

The Optical Transfer Function (OTF) and its modulus the Modulation Transfer Function (MTF) are metrics of optical system performance. However in system optimization, calculation times for the OTF are often substantially longer than more traditional optimization targets such as wavefront error or transverse ray error. The OTF is typically calculated as either the autocorrelation of the complex pupil function or as the Fourier transform of the Point Spread Function. We recently demonstrated that the on-axis OTF can be represented as a linear combination of analytical functions where the weighting terms are directly related to the wavefront error coefficients and apodization of the complex pupil function. Here, we extend this technique to the off-axis case. The expansion technique offers a potential for accelerating OTF optimization in lens design, as well as insight into the interaction of aberrations with components of the OTF.

Computer assisted optimal illumination design is crucial when developing cost-effective machine vision systems. Standard local optimization methods, such as downhill simplex optimization (DHSO), often result in an optimal solution that is influenced by the starting point by converging to a local minimum, especially when dealing with high dimensional illumination designs or nonlinear merit spaces. This work presents a novel nonlinear optimization approach, based on design and analysis of computer experiments (DACE). The methodology is first illustrated with a 2D case study of four light sources symmetrically positioned along a fixed arc in order to obtain optimal irradiance uniformity on a flat Lambertian reflecting target at the arc center. The first step consists of choosing angular positions with no overlap between sources using a fast, flexible space filling design. Ray-tracing simulations are then performed at the design points and a merit function is used for each configuration to quantify the homogeneity of the irradiance at the target. The obtained homogeneities at the design points are further used as input to a Gaussian Process (GP), which develops a preliminary distribution for the expected merit space. Global optimization is then performed on the GP more likely providing optimal parameters. Next, the light positioning case study is further investigated by varying the radius of the arc, and by adding two spots symmetrically positioned along an arc diametrically opposed to the first one. The added value of using DACE with regard to the performance in convergence is 6 times faster than the standard simplex method for equal uniformity of 97%. The obtained results were successfully validated experimentally using a short-wavelength infrared (SWIR) hyperspectral imager monitoring a Spectralon panel illuminated by tungsten halogen sources with 10% of relative error.

Freeform optical surfaces have been in much demand recently due to improved techniques in their manufacturability and design methodology, and the degrees of freedom it gives the designers. Specifically in the case of off-axis mirror systems, freeform surfaces can considerably reduce the number of surfaces and compensate for some of the higher order aberrations as well, which improves the overall system performance. In this paper, we explore the design of freeform surfaces to obtain full aplanatic mirror systems, i.e., free of spherical aberration and circular coma of all orders. It is well know that such a system must be stigmatic and satisfy the Abbe sine condition. This problem is well known (Schwarzschild, 1905) to be solvable with two aspheric when the system has rotational symmetry. Here we prove that a rigorous solution to the general non-symmetric problem needs at least three free form surfaces, which are solutions of a system of partial differential equations. The examples considered have one plane of symmetry, where a consistent 2D solution is used as boundary condition for the 3D problem. We have used the x-y polynomial representations for all the surfaces used, and the iterative algorithm formulated for solving the above mentioned partial differential equations has shown very fast convergence.

A 128-view auto-stereoscopic display using laser-scan and angle-magnifying screen is proposed. On the exit pupil of front projection lens, 8 spots of laser-scanning are provided. The exit pupil of the rear projection lens is doubled by two aperture-relay lenses and 8 spots of laser-scanning are doubled to 16 spots. The angle-magnifying screen comprises the main part of double-lenticular and the attaching part of micro-deflector. With the micro-deflector, angles formed by the laser scanning are deflected into eight angle ranges. With the double-lenticular, eight angle ranges incident into the screen are magnified into a large field of view for the observer. The laser scanning is realized by the vibration of Galvano-mirror that synchronizing with the frame rate of the DMD. For one cycle of vibration by the Galvo-mirror, 16 steps of reflections happen on going and returning paths. For each viewing position, 48 viewing per second are provided. The micro-deflector part comprises the (-4, +4) vertical micro-deflector and the (-1, -1, +1, +3) 45° micro-deflector. Each elements of the micro-deflector are aligned with the images of the pixels that come from the DMD. When a scanning of 16 spots passes different deflecting elements that cover 8 different pixels, the scanning is deflected to eight angle ranges and 128 partitioned viewing zones are formed in the observer plane.

Light-field displays are good candidates in the field of glasses-free 3D display for showing real 3D images without decreasing the image resolution. Light-field displays can create light rays using a large number of projectors in order to express the natural 3D images. However, in light-field displays using multi-projectors, the compensation is very critical due to different characteristics and arrangement positions of each projector. In this paper, we present an enhanced 55- inch, 100-Mpixel multi-projection 3D display consisting of 96 micro projectors for immersive natural 3D viewing in medical and educational applications. To achieve enhanced image quality, color and brightness uniformity compensation methods are utilized along with an improved projector configuration design and a real-time calibration process of projector alignment. For color uniformity compensation, projected images from each projector are captured by a camera arranged in front of the screen, the number of pixels based on RGB color intensities of each captured image is analyzed, and the distributions of RGB color intensities are adjusted by using the respective maximum values of RGB color intensities. For brightness uniformity compensation, each light-field ray emitted from a screen pixel is modeled by a radial basis function, and compensating weights of each screen pixel are calculated and transferred to the projection images by the mapping relationship between the screen and projector coordinates. Finally, brightness compensated images are rendered for each projector. Consequently, the display shows improved color and brightness uniformity, and consistent, exceptional 3D image quality.

A thin and lensless two-dimensional (2D) to three-dimensional (3D) convertible display based on integral imaging using an edge-lit light guide plate (LGP) is proposed with improved optical efficiency. The proposed system is composed of a general flat backlight and an edge-lit LGP which is commonly used in the backlight of LCD and a LC panel. The edge lit LGP is a waveguide (an acrylic sheet) that is drilled by laser to form a diffuser dot array at the bottom and edge illuminated with LEDs. Light from the LEDs is channeled through the waveguide to the opposite side except where it encounters the diffuser dots, which scatter light and cause bright spots to appear. A point light source array for 3D mode is created then. A general flat backlight behind the transparent LGP is turned on for 2D mode meanwhile edge-lit light is turned off. The 2D and the 3D display modes can be simply modulated by turning on different light source. The explanation of the proposed system is provided and the experimental results are also presented.

Features of the application of a novel optical filter with angular selectivity of the light transmission to architectural glazing are considered. The filter consists of a sheet transparent substrate with thin-film grating layers on both surfaces. The gratings formed by directionally transmissive strips, alternating with absorptive, reflective, or scattering strips. Their relative position on the input and output surfaces provides angular selectivity of the directional light transmission – as the incidence angle changes, the proportion of radiation that passes through both gratings of the filter also changes. Chromogenic materials currently used in the laminated smart windows, providing control over the intensity and spectrum of the transmitted solar radiation, cannot achieve the selective regulation on the ranges of incidence angles. Such a regulation requires the use of additional daylight-redirecting devices, especially blinds, to dynamically adapt to the position of the sun. The grating optical filter provides angular selectivity of the light transmission of a window without such devices. The features of using this filter in the single and double glazed windows are described. A graphic analytical calculation method is proposed for estimating the effect of geometrical and optical parameters of the filter on the angular characteristics of the light transmission. An algorithm to optimize filtering solar radiation taking into account the geographical coordinates of terrain, time of day and year and the orientation of the window to the cardinal is set. An algorithm to calculating geometrical parameters of the filter with pre-specified characteristics of the light transmission is obtained.

The continued increase in the capabilities and performance in fiber optic networks today require more robust network designs to allow high consumption of information and thus enable users to have greater capacity and data content. That's why we in the task of analyzing and implementing the concept of flexible optical networks to optimize the use of bandwidth at high transmission rates and improved spectral efficiency, which represents the industry an effective economy, and energy.

Contact lenses are typically measured by the wet-box method because of the high optical power resulting from the anterior central curvature of cornea, even though the back vertex power of the lenses are small. In this study, an optical measurement system based on the Shack–Hartmann wavefront principle was established to investigate the aberrations of soft contact lenses. Fitting conditions were micmicked to study the optical design of an eye model with various topographical shapes in the anterior cornea. Initially, the contact lenses were measured by the wet-box method, and then by fitting the various topographical shapes of cornea to the eye model. In addition, an optics simulation program was employed to determine the sources of errors and assess the accuracy of the system. Finally, samples of soft contact lenses with various Diopters were measured; and, both simulations and experimental results were compared for resolving the controversies of fitting contact lenses to an eye model for optical measurements. More importantly, the results show that the proposed system can be employed for study of primary aberrations in contact lenses.

A type of liquid crystal microlens array (LCMLA) with tunable focal length by the voltage signals applied between its top and bottom electrodes, is fabricated and then the common optical focusing characteristics are tested. The relationship between the focal length and the applied voltage signals is given. The LCMLA is integrated with an image sensor and further coupled with a main lens so as to construct a plenoptic camera. Several raw images at different voltage signals applied are acquired and contrasted through the LCMLA-based plenoptic camera constructed by us. Our experiments demonstrate that through utilizing a LCMLA in a plenoptic camera, the focused zone of the LCMLA-based plenoptic camera can be shifted effectively only by changing the voltage signals loaded between the electrodes of the LCMLA, which is equivalent to the extension of the depth of field.

We investigated pre, post-compensation and symmetrical or hybrid-compensation in the presence of fiber nonlinearities with NRZ, RZ, Raised Cosine and Gaussian modulation formats for 32x10 Gbps system in this work. Analysis is done taking Quality factor and eye diagram at receiver. The simulation results showed that for all the modulation formats as the signal input power increases up to certain limit Q value first increases and then starts decreasing. The symmetric compensation scheme performs better than pre and post compensation techniques for all type of modulation formats except in case of Gaussian format at input signal power 0 dBm. It is also found out that NRZ performs better for lower input signal power and RZ performs better at high input signal powers for symmetric compensation.

In this work we address a comparison study between two kinds of Single Photon Sources (SPS). The first SPS is an Enhanced SPS (ESPS), which consists of an association between InAs/GaAs Quantum Dot (QD) and photonic crystal (PC) microcavity. The ESPS emits a single photon at 1550 nm with probability P1 around 0.7. The second SPS is the Heralded SPS (HSPS) and based on active two-dimensional PC over LiNbO3 and emits photons at 1310 nm and 1550nm. The photon at 1310 nm triggers the detection mechanism of the photon at 1550nm. The probability to obtain a HSPS at 1550 nm is closed to 0.57. Finally, we present a comparison study between ESPS and HSPS when they are used in an application of quantum communication.

This study aims to build a prototype of a new device for measuring by optics, the level of liquids or liquefied gases in tanks without the use of moving parts for general applications, stationary or not, industrial and chemical vehicles. There are a lot of optical devices for measuring liquid level and various settings and runs, some devices with buildings and sophisticated technologies, complicated and more simple, but none of these devices has the configuration (provision and operation), for measuring by optical means, the level of liquids in tanks and reservoirs. That is a simple, efficient and cost effective device.

A test method was developed to find the ideal optical material that supports the chemical reaction of some fuels. Optical plastics and resin were submerged for long periods of time in reservoirs of ethanol, gasoline, Diesel and biodiesel. The dimensional change and weight change of the submerged samples was measured. A special resin successfully supported the chemical attack of fuels. Samples of acrylic polymer and polycarbonate were used as type of optical plastic.

The paper presents formulas for a ray tracing in the optical system of one-mirror and two-mirror optical scanners with a variable focus lens. The procedures for modelling of one-mirror and two-mirror systems, which are used frequently in practice, are described. The result of the analysis describes a general calculation of the position of the beam spot in the detection plane with respect to deflection angles of scanner mirrors. Furthermore, equations for the calculation of the focal length which ensure focusing of a beam at the desired point in a detection plane are derived. The chosen vector approach is general. Thus, the application of the formulas in various configurations of the optical systems is possible. An uncertainty analysis of the position of the beam spot in the detection plane is performed. Using derived formulas one can calculate deflection angles of scanner mirrors and required focal length of the variable focus lens provided that the position of the focused beam in space is given with a required tolerance. Computer simulations are performed on examples of one-mirror and two mirror optical scanners with a variable focus lens.

Here we describe the fabrication and testing of a hollow prism and its application in a spectrograph. A hollow prism with a grating (GRISM) is used as a tunable spectrograph.

Imaging fiber bundles can relay a curved image surface to a conventional at focal plane, effectively providing the curved image sensor needed for some high performance lenses. If the fiber bundle period or image sensor pitch are very different, the system resolution is determined by the oversampled fiber or sensor feature. But crosstalk imposes an approximately 2µm minimum waveguide pitch, and light collection and fabrication constraints impose a lower limit of 1-2µm for the sensor pitch. Maximizing image information leads to some degree of aliasing, which appears in the form of moiré pattern on the raw image sensed. For example, a 30 Mpixel 120° field of view imager using a 1.75µm Bayer filtered CMOS focal plane with 2.5µm pitch fiber bundle yielded images with visible moiré. Here we present a study of moiré effects in fiber-coupled image sensors, including a method for quantitative analysis of moiré, and experimental characterization of the sensors with 1.1µm pixel pitch, the highest spatial resolution in commercially available focal plane arrays. We investigate the effect of exposure time of the sensor, angle of incidence of collimated light, and imaging lens F/# on the raw moiré pattern strength. This study provides guidelines for optimization and operation of high resolution fiber-coupled imagers.