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In this work, we report two multifocal terahertz (THz) lenses (MTLs) based on reflective metasurfaces with focusing efficiencies of 57.3% and 46.3% at a frequency of 3.11 THz, respectively. The reflective metasurfaces were constructed by patterning the polarization-insensitive cross resonator array atop a continuous gold ground plane spaced by a layer of parylene film, which provides a complete 2π phase coverage. The elaborated phase profiles of the two MTLs were arranged based on the Fresnel-Kirchhoff diffraction theory. The two MTLs were theoretically and experimentally verified to converge continuous THz waves into two and four beam spots at their focal planes, respectively. Meanwhile, the MTLs were also experimentally demonstrated with multiple imaging abilities. [ABSTRACT FROM AUTHOR]

This paper proposes a freeform surface lens design based on the Fresnel model to achieve a compact structure and good collimation. A simulation indicates the lens enjoys an efficiency as high as 88.43% within a half view angle of 2° for 1 × 1 mm2 size LED. This paper makes a comparison of three types of lens, among which the Fresnel freeform lens achieves the best performance when the LED size is smaller than 2.5 × 2.5 mm2. The influence of the LED size and the manufacturing tolerances are discussed. [ABSTRACT FROM AUTHOR]

Accommodation-convergence mismatch is still an unsolved issue within the field of augmented reality, virtual reality, and three-dimensional systems in general. Solutions suggested to correct the focus cue in recent years require additional bandwidth, or compromise the image resolution. Our simple approach to overcome this issue is by using an eye-tracking system and electronic lenses. We propose an electronic hybrid lens system composed of segmented phase profile liquid crystal and Pancharatnam phase lenses. For practical application, eye tracking is necessary for measuring the toe-in of the user's pupil to calculate the object depth. This information is used to determine the required diopteric power of the hybrid system. The optical performance and imaging quality of the proposed hybrid system are evaluated. [ABSTRACT FROM AUTHOR]

System assessment for design often involves averages, such as the standard deviation of the wavefront error, which are estimated by ray tracing through a sample of points within the entrance pupil. General-purpose sampling and weighting schemes are presented, and it is also shown that optical design can benefit from tailored versions of these schemes. It turns out that the type of Gaussian quadrature that has long been recognized for efficiency in this domain requires about 40% to 50% more ray tracing to attain comparable accuracy to generic versions of the new schemes. Even greater efficiency gains can be won, however, by tailoring such sampling schemes to the optical context where azimuthal variation in the wavefront is generally weaker than the radial variation. These new schemes are special cases of what is known in the mathematical world as cubature. Our initial results also led to the consideration of simpler sampling configurations that approximate the newfound cubature schemes. We report on the practical application of a selection of such schemes and make observations that aid in the discovery of cubature schemes relevant to optical design of systems with circular pupils. [ABSTRACT FROM AUTHOR]

Mounting aspheres is often challenging because of the higher sensitivity to decenter and tilt compared with spherical lenses. This paper first describes aspheric surface decenter and tilt error as per ISO 10110 standard. Then, the most common lens mounting and alignment method for aspheric lenses are discussed in detail. Finally, an innovative mounting method that uses surface contact mounting is presented. This autocentering method uses the optical surfaces as mounting interfaces to provide a high level of centering accuracy for aspheric lenses. Centering measurement results for different aspheric lenses mounted using this method are also presented. [ABSTRACT FROM AUTHOR]

Gabor's 1941 catadioptric design can be modified to give much higher performance versions. Some designs are shown that are 0.999 NA in air over a wide field with diffraction-limited correction on a curved image. [ABSTRACT FROM AUTHOR]

Hard x-ray lenses are useful elements in x-ray microscopy and in creating focused illumination for analytical applications such as x-ray fluorescence imaging. Recently, polymer compound refractive lenses for focused illumination in the soft x-ray regime (< 10 keV) have been created with nano-printing. However, there are no such lenses yet for hard x-rays, particularly of short focal lengths for benchtop microscopy. We report the first instance of a nano-printed lens for hard x-ray microscopy, and evaluate its imaging performance. The lens consists of a spherically focusing compound refractive lens designed for 22 keV photon energy, with a tightly packed structure to provide a short total length of 1.8 mm and a focal length of 21.5 mm. The resulting lens technology was found to enable benchtop microscopy at 74x magnification and 1.1 μm de-magnified image pixel size at the object plane. It was used to image and evaluate the focal spots of tungsten-anode micro-focus x-ray sources. The overall system resolution with broadband illumination from a tungsten-anode x-ray tube at 30 kV and 10 mm focal distance was measured to be 2.30±0.22 μm. [ABSTRACT FROM AUTHOR]

The canonical form of an optical plasma lens is a parabolic density channel. This form suffers from spherical aberrations, among others. Spherical aberration is partially corrected by adding a quartic term to the radial density profile. Ideal forms which lead to perfect focusing or imaging are obtained. The fields at the focus of a strong lens are computed with high accuracy and efficiency using a combination of eikonal and full Maxwell descriptions of the radiation propagation. The calculations are performed using a new computer propagation code, SeaRay, which is designed to transition between various solution methods as the beam propagates through different spatial regions. The calculations produce the full Maxwell vector fields in the focal region. [ABSTRACT FROM AUTHOR]

We demonstrate a new method for realizing Luneburg lens antennas with nearly continuously graded permittivity profiles in three dimensions. The method combines fused filament fabrication, a nearly ubiquitous additive manufacturing technique, with an effective media approach that employs space-filling curves. We experimentally validate our design methodology by fabricating and characterizing two Luneburg lenses designed to operate at separate frequency bands (26–40 GHz and 70–110 GHz) with antenna gains of 20 and 24 dBi, respectively. The results demonstrate good agreement with rigorous electromagnetic simulations. We also demonstrate the ability to passively beam steer over a wideband of operation (26–40 GHz and 70–110 GHz) with less than 0.5% power loss due to dielectric material losses within the Luneburg lens. [ABSTRACT FROM AUTHOR]

We showthe existence of a lens, when its lower face is given, such that it refracts radiation emanating from a planar source, with a given field of directions, into the far field that preserves a given distribution of energies. Conditions are shown under which the lens obtained is physically realizable. It is shown that the upper face of the lens satisfies a pde of Monge-Ampère type. [ABSTRACT FROM AUTHOR]

Simple lenses with spherical surfaces are lightweight, inexpensive, highly flexible, and can be easily processed. However, they suffer from optical aberrations that lead to limitations in high-quality photography. In this study, we propose a set of computational photography techniques based on sparse signal representation to remove optical aberrations, thereby allowing the recovery of images captured through a single-lens camera. The primary advantage of the proposed method is that many prior point spread functions calibrated at different depths are successfully used for restoring visual images in a short time, which can be generally applied to nonblind deconvolution methods for solving the problem of the excessive processing time caused by the number of point spread functions. The optical software CODE V is applied for examining the reliability of the proposed method by simulation. The simulation results reveal that the suggested method outperforms the traditional methods. Moreover, the performance of a single-lens camera is significantly enhanced both qualitatively and perceptually. Particularly, the prior information obtained by CODE V can be used for processing the real images of a single-lens camera, which provides an alternative approach to conveniently and accurately obtain point spread functions of single-lens cameras. [ABSTRACT FROM AUTHOR]

Electric-field-driven liquid crystal (ELC) lens with tunable focal length and their depth of field has been extensively applied in 3D display and imaging systems. In this work, a dual-layer electrode-driven liquid crystal (DELC) lens with electrically tunable focal length and controllable focal plane is demonstrated. ITO–SiO 2 -AZO electrodes with the dual-layer staggered structure on the top substrate are used as driven electrodes within a LC cell, which permits the establishment of an alternative controllability. The focal length of the DELC lens can be adjusted from 1.41 cm to 0.29 cm when the operating voltage changes from 15 V to 40 V. Furthermore, the focal plane of the DELC lens can selectively move by changing the driving method of the applied voltage to the next driven electrodes. This work demonstrates that the DELC lens has potential applications in imaging systems because of electrically tunable focal length and controllable focal plane. [ABSTRACT FROM AUTHOR]

Abstract: A crucial disanalogy between Twin Earth and Inverted Earth undermines qualia‐internalism. A recent transplant to Inverted Earth has been equipped with color‐inverting contact lenses, so that she is unable to see the colors of objects whereas a recent transplant to Twin Earth can see twater. It is implausible to think that time alone could rectify this perceptual shortcoming – that the passage of time could alter the contents of her visual perceptions or the meaning of her color terms. Thus, the thought experiment does not refute the close tie between phenomenology and representation in the case of color. [ABSTRACT FROM AUTHOR]

Diffraction is a source of distortion in optical imaging, and can be nearly eliminated by linear compensating components such as lenses. However, in many applications such components are impractical, and thus the ongoing interest in simple low-cost solutions. Since standard detection is based on power measurements (rather than coherent field measurements) a simple linear filter cannot compensate for the distortions. However, if the variations in the image are relatively small the process is approximately linear and can be compensated by applying a linear filter. This approach has been developed, however, the analysis was always done in the spectral domain, in which case electrical spectral filters cannot be easily implemented on a 2D matrix without digital processing. We present a spatial filter for diffraction compensation in the spatial domain, based on a filter which was originally developed by us for dispersion mitigation. To the best of our knowledge, this is the first time that an analytical expression is derived for a diffraction compensating filter in the spatial domain. Moreover, in previous works a small imaginary parameter was introduced to eliminate divergence. In the present paper a simple analytical evaluation of this parameter is given, which eliminates the need for iterative computations. [ABSTRACT FROM AUTHOR]

In this work, the authors developed a deep reactive ion etching (DRIE) process to fabricate x-raynano- lenses and so-called adiabatic focusing lenses made of silicon. Based on the photolithographic fabrication of excellent etch masks, including a continued adjustment of the pattern layout and the application of a novel developed so-called semicontinuous DRIE process, the creation of several generations of silicon lenses was realized. This process enabled us to fulfill the extreme high demands on the pattern quality, which are an aspect ratio up to 10:1, a tilt angle of 90±0.5°, a mask undercut⩽100 nm, parallelism of the sidewalls, and a surface roughness lower than 50 nm. Using this etching process, the authors successfully created patterns for x-ray-lenses in silicon with lateral dimensions from 20 μm down to 1 μm and etch depths of 19 μm for the 20- μm-lenses and 10- μm for the 1-μm-lenses. [ABSTRACT FROM AUTHOR]

We present the design of a new switchable multi-focal lens which consists of a freeform lens and a programmable spatial light modulator (SLM). By rapidly switching the input light path through different segments of the freeform lens with the programmable SLM, multiple foci are created in a time-multiplexed fashion. While the proposed multi-focal lens method can have a broad range of applications in imaging and display systems, we experimentally demonstrate a proof of concept prototype for an imaging system. [ABSTRACT FROM AUTHOR]

We proposed a lens design procedure to generate parallel light beams that facilitate optical MIMO communication with negligible interference between the un-intended transceiver pairs, in a 2×2 LED array. We designed an imaging receiver using two aspheric lenses instead of one single hemispherical lens to improve the light-beam separation performance. The proposed scheme can be extended to the scenario with ultra-dense LED array. Numerical results show that proper parameter setting in lens design can lead to negligible interference between un-intended transceiver pairs. The bit error rate performance is also evaluated. [ABSTRACT FROM AUTHOR]

Conventional compact spectrometers have a fixed spectral resolution and cannot resolve the polarization properties of light without additional optical elements, while their larger counterparts are bulky and costly. Here, we demonstrate multiple offaxis meta-lenses in the visible integrated on a single planar substrate. They possess both focusing and strongly dispersive properties and are designed to provide different spectral resolutions as well as working wavelength ranges on the same chip. We realize a compact spectrometer using only these meta-lenses and a CMOS camera and achieve detector-limited spectral resolutions as small as 0.3 nm and a total working wavelength range exceeding 170 nm for a beam propagation length of only a few cm. In addition, this spectrometer has the capability to resolve different helicities of light in a single measurement. This chip-camera setup represents the most compact configuration so far achieved for a spectrometer with similar performance and functionality, and its compatibility with large-scale fabrication processes makes it broadly applicable. © 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license [ABSTRACT FROM AUTHOR]

Sensor resolution of 3D time-of-flight (ToF) outdoor-capable cameras is strongly limited because of its large pixel dimensions. Computational imaging permits enhancement of the optical system's resolving power without changing physical sensor properties. Super-resolution (SR) algorithms superimpose several sub-pixel-shifted low-resolution (LR) images to overcome the system's limited spatial sampling rate. In this paper, we propose a novel opto-mechanical system to implement sub-pixel shifts by moving an optical lens. This method is more flexible in terms of implementing SR techniques than current sensor-shift approaches. In addition, we describe a SR observation model that has been optimized for the use of LR 3D ToF cameras. A state-of-the-art iteratively reweighted minimization algorithm executes the SR process. It is proven that our method achieves nearly the same resolution increase as if the pixel area would be halved physically. Resolution enhancement is measured objectively for amplitude images of a static object scene. [ABSTRACT FROM AUTHOR]

This paper describes a method for designing an ultraviolet (UV) projection lens for microlithography. Our approach for meeting this objective is to use a starting design automatically obtained by the DSEARCH feature in the SYNOPSYS? lens design program. We describe the steps for getting a desired starting point for the projection lens and discuss optimization problems unique to this system, where the two parts of the projection lens are designed independently. [ABSTRACT FROM AUTHOR]

Previous designs of conventional aerodynamic lens have been widely used to focus large nanoparticles. It is a big challenge to focus small sub-10 nm nanoparticles. The focusing of small nanoparticle is controlled by two factors: high diffusivity and low inertia. Here, we made some modification for the aerodynamic lens system designed by Wang et al. (Aerosol Sci Technol 39:624, 1). The capability of focusing sub-10 nm nanoparticles was evaluated by the computational fluid dynamics software FLUENT. From numerical simulations of size-resolved particle trajectories, it was found that most of the small nanoparticles lost to the wall by diffusion. The effect of Brownian diffusion on the particle extraction from lens system is investigated. Simulations have shown that the Brownian diffusion perturbs the trajectories of nanoparticles that are dictated by the carrier gas and increase the probability of nanoparticle deposition on the wall. The effect of lens system geometry on the nanoparticles is also investigated. The results of simulation showed that the geometry of lens system affected the beam diameter and the transmission efficiency of nanoparticle. [ABSTRACT FROM AUTHOR]

When optoelectronic systems (OES) are used for control purposes in mechanical engineering, there is a risk of objective cracking caused by collision with hard particles of the environment. The article shows that it is possible to reduce the objective lens diameter two times without loss of resolution, and thus to improve impact resistance by reducing the probability of collision and objective lens cracking. [ABSTRACT FROM AUTHOR]

The article discusses the role of refractive lenses for microscopy and nanoanalysis. It mentions that many materials have been tested for the purpose of manufacturing of X-ray lenses such as aluminum lenses. It also reveals that most common applications of X-ray optics is the generation of small beams for micro and nanoanalysis.

The article provides an analysis of the development of Hard X-ray focusing optics at diamond light source. Topics discussed include research and development in design and fabrication of refractive lenses, role of single crystal silicon micro-machining in delivering most accurate fabricated lenses, and single crystal diamond as an ideal material for X-ray optics.

Based on the edge-ray principle of non-imaging optics, an optical design method for a lens producing small angle, uniform illumination from a high-power light-emitting diode light source has been developed. The energy correspondence between the light-emitting diode light source and the illuminance distribution on a target plane was established, and a number of discrete points for freeform profile curves which could achieve uniform illumination over a small angle were calculated and fitted to create a lens. Finally, simulations were performed using software. The influence of the size of light source on the emitting angle under uniform illumination was also investigated. The results show that the optical system can achieve uniform illumination with an extended source, the divergence angle being controlled within a minimum range by the optical design method. [ABSTRACT FROM AUTHOR]

In this work, we present a new systematic technique for the design of a flat lens using modified commercial off-the-shelf (COTS) materials, as opposed to metamaterials (MTMs) that are often required in lens designs based on the Transformation Optics (TO) approach. While lens designs based on Ray Optics (RO) do not suffer from the drawback of having to use metamaterials, they still require dielectric materials that may not be commercially available off-the-shelf. This paper describes a systematic procedure for realizing the desired materials by modifying the COTS types, and illustrates its application with some practical examples. [ABSTRACT FROM AUTHOR]

Several designs are shown, which are alternatives to Bernhard Schmidt's largely unknown 1934 three-lens corrector replacement for an aspheric plate in his famous telescope. [ABSTRACT FROM AUTHOR]

Purpose To describe and to experimentally assess a new intraocular lens (IOL) design using new diffractive technology. Setting AMO Groningen b.v., Groningen, Netherlands. Design Experimental study. Materials and methods The basic principles of the new diffractive technology are described. The new IOL comprises two diffractive technologies; one is designed to extend the range of vision by elongating the focus, and the other increases the retinal image contrast by correcting chromatic aberration. To assess the potential visual performance, simulations were carried out in clinically verified eye models to predict the clinical defocus curves (visual acuity). The optical performance of the new lens design was evaluated by optical measurements in a model eye. The model eye had a cornea having the spherical aberration and chromatic aberration of an average cataract patient. The measurements were performed in white light and monochromatic light. Results The simulations suggested an increase in visual acuity of 0.27 logMAR as compared to an aspherical monofocal IOL in the range from −1 to −3 diopter defocus. The white light modulation transfer function in the far focus was identical to that of a monofocal IOL. The new lens demonstrated negative chromatic aberration, therefore showing the capability to actively reduce ocular chromatic aberration. The experiments also show retinal image characteristics of an extended light source that suggest that dysphotopsias (halos) of the new IOL are comparable to those associated with monofocal IOLs. Conclusions The application of new IOL diffractive technology enabled optical characteristics that suggested that an extended range of vision can be obtained without compromising distance vision. Financial Disclosure All authors are employees of Abbott Medical Optics, Inc. [ABSTRACT FROM AUTHOR]

Optical design for an integrated light source is currently a hot topic, but it is also difficult due to the complexity of the calculations. In this paper, based on the edge-ray principle and the grid division method, two types of lenses for creating a 3:1 uniformly illuminated rectangular spot and 1:1 uniformly illuminated square spot are designed. Research results show that when the ratio of the size of the LED light source to the lens height is 1:10 and 1:5, i.e. it is equivalent to a point source, the uniformity of illuminance on the target surface is as high as 90%, and the system energy utilisation is 88%. When the ratio of the size of the LED source to the lens height is 1:3.3, 1:2.5 or 1:2.0, i.e. the equivalent of an extended source, the uniformity of illuminance on the target surface is more than 80% and the system energy utilisation is about 88%. This means the lenses can maintain the high energy efficiency and illuminance uniformity for an extended source. Tolerance analyses were also conducted. It seems that the illumination uniformity is sensitive to light source installation errors, but when the offset of the LED from the lens is less than 0.2 mm, illumination uniformity is maintained at a high level. [ABSTRACT FROM AUTHOR]

A practical method is proposed to design a double freeform surfaces (DFS) lens for LED sources, in order to form uniform illumination in the high distance–height ratio (DHR) lighting system. The ray mapping relationship is first established between the solid angle of the source and the target plane according to the energy conservation law and the variable separation method. A DFS lens is then constructed simultaneously and point by point to the ray mapping based on the Snell's law. Optical performance of the lens is investigated by the Monte Carlo method. A simple and effective method is utilized to optimize the lens design in accordance with the simulation results. As an example, a DFS lens with DHR of 2.5 (distance 30 mm, height 12 mm) is designed by the proposed method. Compared with the traditional methods, the illuminance uniformity is significantly improved from 67.20% to 86.43% and the size of the lens is dramatically reduced. [ABSTRACT FROM AUTHOR]

We report here a design method based on smart transformation optics (STO) to control the range of the permittivity values of the materials required to manufacture transformation optics devices. In particular, we show that it is possible to reduce the maximum electric permittivity value required to realize a STO device with certain functionality by means of a simple conceptual elastic stretching process. We illustrate the design procedure with two types of collimator meta-lens designs, which we call warping space collimator meta-lens and half fisheye collimator meta-lens, respectively. We provide design examples of these two types of lenses with the help of COMSOL Multiphysics software. These two design examples are fabricated with commonly available dielectric materials by means of 3D printing technology. For the functional verification of these two collimator lenses, we provide measurement results obtained with transverse electric waves of frequency range 7-13GHz. [ABSTRACT FROM AUTHOR]

Background Incorrect lens power remains one of the most common reasons for intraocular lens explantation/exchange. We evaluated stability and effect on capsular bag opacification of a new foldable modular lens system, with a base component and an optic component in rabbit eyes. Methods Bilateral phacoemulsification was performed on six rabbits; one eye received the test lens ( Harmoni Modular Lens, ClarVista Medical), whereas the other received a single-piece hydrophobic acrylic control lens ( SA60AT, Alcon). Slit-lamp examinations were performed at postoperative weeks 1, 2, 3, 4 and 6. All rabbits were sacrificed at week 6. After enucleation, the eyes were examined grossly from the Miyake- Apple view. Following, all globes were sectioned and processed for histopathological examination. Results The modular lens was stable in all six rabbits. Uveal biocompatibility was similar to or better in the test eyes when compared with control eyes up to 6 weeks postoperatively. Overall, capsular bag opacification was found to be significantly lower in the test eyes when compared with control eyes. At the 6-week gross examination, central posterior capsule opacification was scored as 0.58 ± 0.73 in the test group, and as 3.00 ± 1.26 in the control group (paired two samples for means t-test; two-tail P = 0.005). Conclusions The Harmoni Modular system remains stable within the capsular bag after implantation. Due to the design of the base component featuring long loops, along with peripheral anterior and posterior square edges, the lens appeared to prevent overall capsular bag opacification in the rabbit model. [ABSTRACT FROM AUTHOR]

An antenna with a wide scan angle in a wide frequency band is obtained by feeding a conformal arc array with a modified formulation of Rotman lens design. In this paper, two kinds of Rotman lenses are designed to feed a linear array and a conformal array and their scan angles are compared in a specified frequency band. The phase distributions of the linear array elements are linear in all scan angles, but these phase distributions are nonlinear in the conformal array. Therefore in order to design a Rotman lens for conformal arrays, the conventional Rotman lens design formulations must be modified. For this purpose, first the phase distributions of conformal array elements were obtained using the particle swarm optimization (PSO) process. Then by modifying the conventional Rotman Lens design formulations used for linear arrays, appropriate formulations for conformal arrays are obtained. In the end, by selecting two specified linear and conformal arrays with equal number of elements, their maximum scan angles in a specified frequency band are studied. It is shown that in the same frequency band the maximum scan angle increases about 20% in the Rotman Lens fed conformal array antenna. [ABSTRACT FROM AUTHOR]

This paper proposes using a liquid lens as a compensating lens and applying intermediate optics to achieve a 9x zoom ratio. The droplet shape and location of the liquid lens can be adjusted reversibly, enabling the focal length and position of the lens to be tuned by varying the voltage applied to a set of electrodes. Therefore, liquid lenses can replace complex lenses to reduce the total length of optomechanical systems. The CODE V built-in optimization method was used to determine the optimal liquid lens parameters at various zoom ratios. Several general optical aberrations were considered. Compared with a standard intermediate optics system featuring 9x zoom and no compensating lens, the proposed lens improved the Petzval surface curvature (PTZ) and modulation transfer function (MTF). Simulation results revealed that the PTZ decreased 10.92% and the MTF increased 3988% in 40 1p/mm. [ABSTRACT FROM AUTHOR]

Need for high-performance and sophisticated optical devices in the terahertz wave band is growing rapidly with terahertz technological progress. This paper presents a lens in the terahertz wave band based on phase control using an oblique metal slit array. A convex oblique slit array can produce a focusing effect. This focusing effect is confirmed by full-wave analysis for the designed terahertz path-length lens. The effective refractive index computed from the full-wave analysis is consistent with analytical expressions and changes from 1.00 to 1.56 with the angle of the metal slit array. Full-wave analysis also confirms that the lamination errors of the path-length lens have limited influence on the focusing effects. The robustness of the lens design is essential for its industrial applications to terahertz optical devices. [ABSTRACT FROM AUTHOR]

The article is a study on the use of an achromatic objective lens as a versatile imaging interface for high-lateral-resolution atmospheric pressure (AP) matrix assisted laser desorption ionization (MALDI) mass spectrometric imaging. It mentions the issues faced while using chromatic lenses and also discusses the various properties of achromatic objective lens which makes it ideal for MALDI Mass Spectrometric Imaging, used for bio marker discovery and disease diagnosis in bio clinical research.

Diffractive lenses are expected to improve a chromatic aberration and a field curvature of optical systems. However, for capturing a color image, the quality of the image is reduced due to unnecessary diffractive light. This paper shows a novel diffraction grating lens with nanocomposite material, and the design method of the lens for imaging use. [ABSTRACT FROM AUTHOR]

To focus hard X- and γ-rays it is possible to use a Laue lens as a concentrator. With this optics it is possible to improve the detection of radiation for several applications, from the observation of the most violent phenomena in the sky to nuclear medicine applications for diagnostic and therapeutic purposes. We implemented a code named LaueGen, which is based on a genetic algorithm and aims to design optimized Laue lenses. The genetic algorithm was selected because optimizing a Laue lens is a complex and discretized problem. The output of the code consists of the design of a Laue lens, which is composed of diffracting crystals that are selected and arranged in such a way as to maximize the lens performance. The code allows managing crystals of any material and crystallographic orientation. The program is structured in such a way that the user can control all the initial lens parameters. As a result, LaueGen is highly versatile and can be used to design very small lenses, for example, for nuclear medicine, or very large lenses, for example, for satellite-borne astrophysical missions. [ABSTRACT FROM AUTHOR]

Two different multilayer Laue lens designs were made with total deposition thicknesses of 48 μm and 53 μm, and focal lengths of 20.0 mm and 12.5 mm at 20.0 keV, respectively. From these two multilayer systems, several lenses were manufactured for one- and two-dimensional focusing. The latter is realised with a directly bonded assembly of two crossed lenses, that reduces the distance between the lenses in the beam direction to 30 μm and eliminates the necessity of producing different multilayer systems. Characterization of lens fabrication was performed using a laboratory X-ray microscope. Focusing properties have been investigated using ptychography. [ABSTRACT FROM AUTHOR]

Currently, maintaining image quality during conjugate change is most frequently achieved through careful lens design with the multiconfiguration optimizing method and physical shifts of the lenses within the system such that the system remains in focus. However, in applications with operational limitations, such as endoscopy where the space available cannot allow for moving parts, the lens system needs to be designed such that the system is in focus over a wide range of conjugates. A lens design method that is integrable into existing commercial lens design software is presented. This method derives and maintains an optimal condition for astigmatism and distortion to control and reduce the overall aberration variation during the conjugate change, and extends the depth of field of the system. A side-by-side lens design comparison between the method illustrated in this study and the conventional lens design method commonly employed by designers of zoom lenses is also presented and is demonstrated to produce better results in designing conjugate change optical systems. [ABSTRACT FROM AUTHOR]

Optical design of an image magnifier based on a lens array is presented. The proposed image magnifier does not have a limit for object size due to off-axis aberration because the object is divided into segments and is kept apart from the nearest neighbor segment with the period of the lens array. Several images can be sequentially generated by magnifying sequentially specific objects among mosaic objects, which are composed of multi-images. The designed lens for the image magnifier corresponds to a lens array with an aperture of 2 mm and a magnification ratio of 3. Furthermore, an application for a display system of the designed image magnifier is also presented. [ABSTRACT FROM AUTHOR]