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This study aims to visualize the motion of an underdamped torsional oscillator using an optical lever. This involves employing an optical setup to magnify and measure the angular displacement of the torsional oscillator as it undergoes oscillations and damps over time. By analysing a video recording of an image of a filament formed by a concave mirror attached to the damped torsional oscillator, we observed an exponential decay in the time-averaged amplitude. [ABSTRACT FROM AUTHOR]

The neutron flux is a crucial factor for neutron scattering measurements, especially for compact sources. Among various neutron optics, grazing‐incidence focusing mirrors have been developed to give a significant increase in the neutron flux on a sample owing to their great potential for collecting neutrons in small‐angle neutron scattering (SANS) instruments. Focusing mirrors with a supermirror coating can be nested to collect a neutron beam with large divergence. Nested conical integrated assembly technology is employed to manufacture nested focusing mirrors. This study describes the design of ten‐shell nested fully annular quasi‐ellipsoidal focusing mirrors with an m = 3 Ni/Ti supermirror coating to produce enough neutrons on a sample under the premise of satisfying the specified minimum wavevector transfer Q. For fully annular focusing mirrors, the neutron current received by a sample from the entire annular focusing neutron beam is more relevant. A ray‐tracing method and current gain calculation are used to evaluate the performance of the designed mirrors. The ray‐tracing result shows that the ideal resolution of quasi‐ellipsoidal mirrors with four‐segment conical approximation is 1.354 mm. As the source radius decreases from 20 mm, the neutron current with the designed focusing mirrors can be enhanced by a factor of 13 to over 100 compared with that without focusing mirrors in the same detected area. The effective collecting area is 186 cm2 when the source radius is the optimal 15 mm. An 83‐fold current gain can be obtained for cold neutrons. The proposed mirrors can reach 90.7 and 87.3% of the maximum current of the corresponding optimal mirror structure when the source radii are 10 and 20 mm, respectively. The results demonstrate that the proposed mirrors are adaptable for instruments with changeable sources. [ABSTRACT FROM AUTHOR]

In this experiment we have first determined the focal length of an equiconvex lens. We have observed that a real image can be formed by the lens on the same side of the source if the source is sufficiently strong. This is due to the reflection from the concave surface of the lens. We have measured these image distances for different object distances. From these measurements, we have determined the refractive index of the lens as well as its radii of curvature. The relationship between the object and image distances in the reflection from the concave surface of a lens as formulated here, is similar to the ordinary reflection from a concave mirror. However, the focal length, in this case, turns out to be smaller than that of a regular concave mirror of the same radius of curvature by a factor of two, for a lens of refractive index of 1.5. [ABSTRACT FROM AUTHOR]

Neutron reflectometry (NR) is a powerful tool for providing insight into the evolution of interfacial structures, for example via operando measurements for electrode–electrolyte interfaces, with a spatial resolution of nanometres. The time resolution of NR, which ranges from seconds to minutes depending on the reflection intensity, unfortunately remains low, particularly for small samples made of state‐of‐the‐art materials even with the latest neutron reflectometers. To overcome this problem, a large‐area focusing supermirror manufactured with ultra‐precision machining has been employed to enhance the neutron flux at the sample, and a gain of approximately 100% in the neutron flux was achieved. Using this mirror, a reflectivity measurement was performed on a thin cathode film on an SrTiO3 substrate in contact with an electrolyte with a small area of 15 × 15 mm. The reflectivity data obtained with the focusing mirror were consistent with those without the mirror, but the acquisition time was shortened to half that of the original, which is an important milestone for rapid measurements with a limited reciprocal space. Furthermore, a method for further upgrades that will reveal the structural evolution with a wide reciprocal space is proposed, by applying this mirror for multi‐incident‐angle neutron reflectometry. [ABSTRACT FROM AUTHOR]

We demonstrated a Si-based concave micromirror array for cell trapping that was fabricated by XeF2 vapor etching. We also examined the optical properties of the focal image of each concave micromirror. In addition, yeast cell trapping was realized at the focal point of a concave micromirror of approximately 35 µm diameter by Köhler illumination using a halogen lamp. The proposed process is useful for the microfabrication of various Si-based microstructure devices, such as microchannels and micro-electromechanical systems (MEMS). [ABSTRACT FROM AUTHOR]

Abstract This paper introduces an effective technique of ameliorating free-space optical (FSO) communication whenever the line-of-sight (LOS) between the end-to-end link nodes is obstructed. Additionally, we also present a novel statistical technique of estimating FSO channel state information (CSI) for analysing the link performance in terms of system BER and short duration deep fades whenever a laser signal traverses a turbulent FSO channel. The consistency of the proposed CSI estimation method is experimentally evaluated over a test-bed FSO link in a laboratory controlled weak turbulence conditions. The numerical results reveal that the CSI-assisted receiver sensitivity at BER =10−9 under weak turbulence is improved by 16.36 % as against the fixed threshold based detector. Based on the experimental outcomes, the scintillation rate is observed to be reduced by 45.26 %, while the statistical results indicate that the requisite power penalty to achieve outage of 10−9 in weak turbulence is reduced by 2.2 dB when a concave reflector is incorporated instead of plane optical reflector for bridging the FSO communication in an obstructed LOS link. [ABSTRACT FROM AUTHOR]

We report a simple technique for the realization of fiber-based Fabry-Pérot microcavities with large Q/V values as well as high cavity-to-fiber coupling efficiencies. The open microcavity we demonstrate consists of a flat mirror and a concave mirror on the tip of a single mode optical fiber. Combining hydrofluoric acid chemical wet etching with CO2 laser reflow, we obtain a fiber-tip atomically smooth concave surface with a diameter of 4.7 μm determined by the fiber core size. The concave surface with a spherical profile is automatically aligned with the fiber core, which enables high cavity-to-fiber power coupling efficiency (higher than 90%) with an optimal fiber-tip mirror's radius of curvature based on numerical simulation results. After distributed-Bragg-reflector coating, we have realized a wavelength-tunable open microcavity with a quality factor Q exceeding 1000 and a mode volume V of 13.6 μm3, and laser emission is demonstrated from this microcavity. [ABSTRACT FROM AUTHOR]

Non‐touch detection of rhodamine B concentration in distilled water using fiber coupler and concave mirror (CM) successfully demonstrated. Based on displacement sensor, the concentration of rhodamine B is detected through the peak voltage value which is resulted from the displacement profile. Using the He‐Ne (543 nm) laser as the source, the fiber coupler as the sensor probe and CM with the curvature radius of 12 mm as the reflector as well as the sample container, the rhodamine B concentration can be detected in the range 0‐20 ppm and the resolution of 0.26 ppm. [ABSTRACT FROM AUTHOR]

Abstract An accurate, practicable, wide-range measurement system for the radius of curvature of spherical concave mirrors using resonant mode spacing measurements of a Fabry–Pérot (FP) cavity without moving parts was developed in this study. Radius of curvature measurements for radii ranging from 500 to 5000 mm were successfully demonstrated with a repeatability of better than 3 × 10−5 using a sequential optical frequency locking procedure. The proposed measurement system was realized using a low-finesse FP cavity under ambient air conditions with few changes made to the settings for changing the target value of radius of curvature. Highlights • An accurate and wide-range measurement system for the radius of curvature was developed. • The proposed measurement system was realized using a low-finesse FP cavity under ambient air conditions. • A sequential optical frequency locking procedure was proposed to reduce the error. • Radius of curvature measurements from 500 to 5000 mm were demonstrated with a repeatability of better than 3 × 10−5. [ABSTRACT FROM AUTHOR]

The non‐monochromatic beamline BL1 at the FLASH free‐electron laser facility at DESY was upgraded with new transport and focusing optics, and a new permanent end‐station, CAMP, was installed. This multi‐purpose instrument is optimized for electron‐ and ion‐spectroscopy, imaging and pump–probe experiments at free‐electron lasers. It can be equipped with various electron‐ and ion‐spectrometers, along with large‐area single‐photon‐counting pnCCD X‐ray detectors, thus enabling a wide range of experiments from atomic, molecular, and cluster physics to material and energy science, chemistry and biology. Here, an overview of the layout, the beam transport and focusing capabilities, and the experimental possibilities of this new end‐station are presented, as well as results from its commissioning. [ABSTRACT FROM AUTHOR]

In this paper, we present a rotational symmetry for an ultrashort throw (UST) lens with offset field. The UST lens has a throw ratio of 0.23 and a total track of 195 mm. The optical elements of the UST lens are comprised of two parts. First, a catadioptric projection lens where the catadioptric function permits reaching an ultrashort throw ratio, short total track, while at the same time requiring fewer lens elements. The second part is a collimating lens which takes advantage of the telecentric condition to generate uniform total internal reflection (TIR) in the TIR prism. With this design, an effective focal length of -1.96 mm and a f-number of 2.4 can be obtained. The root mean square spot size and lateral colour of all fields are smaller than one pixel in size. The maximum optical distortion of −0.97% and TV distortion of 0.2% are acceptable. In terms of image quality, the modulation transfer function (MTF) values for all fields are above 0.65 at 0.245 line pairs/mm. Even when the tolerance error is considered, the MTF values for all fields are still above 0.3. The suitability of the novel UST lens design for projection applications is discussed. [ABSTRACT FROM AUTHOR]

We demonstrate a type of microcavity with large tunable splitting of polarization modes. This polarization nondegenerate cavity consists of two ellipsoidal concave mirrors with controllable eccentricity by CO2 laser machining on fiber end facets. The experiment shows that the cavities can combine the advantages of high finesse above 104 and large tunable polarization mode splitting to the GHz range. As the splitting of the cavity can be finely controlled to match atom hyperfine levels or optomechanics phonons, it will blaze a way in experiments on cavity quantum electrodynamics and cavity optomechanics. [ABSTRACT FROM AUTHOR]

Detection of magnesium ion concentration was successfully demonstrated using a fiber coupler based displacement sensor probe in conjunction with a concave mirror target. Analysis of peak voltage result, which was obtained by moving a sensing port displacement from a fixed concave mirror (CM) was found to be useful to detect a magnesium ion concentration, which is filled in between the probe and target. The proposed sensor is capable for measuring magnesium ion with variation of concentration 0–5%. The resolution of the sensor can be achieved at 0.2%. It was also observed that the use of CM with a longer focal length improves the sensitivity of the sensor. The high sensitivity, the small size, the ease fabrication process, and the bio-compatibility of the proposed device are appealing characteristics that makes it ideal for practical bio-sensing applications. [ABSTRACT FROM AUTHOR]

Neutron radiography is a powerful method of probing the structure of materials based on attenuation of neutrons. This method is most suitable for materials containing heavy metals, which are not transparent to X-rays, for example irradiated nuclear fuel and other nuclear materials. Neutron radiography is one of the first non-distractive post-irradiated examination methods, which is applied to gain an overview of the integrity of irradiated nuclear fuel and other nuclear materials. However, very powerful gamma radiation emitted by the samples is damaging to the electronics of digital imaging detectors and has so far precluded the use of modern detectors. Here we describe a design of a neutron microscope based on focusing mirrors suitable for thermal neutrons. As in optical microscopes, the sample is separated from the detector, decreasing the effect of gamma radiation. In addition, the application of mirrors would result in a thirty-fold gain in flux and a resolution of better than 40 μ m for a field-of-view of about 2.5 cm. Such a thermal neutron microscope can be useful for other applications of neutron radiography, where thermal neutrons are advantageous. [ABSTRACT FROM AUTHOR]

Scallops possess a visual system comprising up to 200 eyes, each containing a concave mirror rather than a lens to focus light. The hierarchical organization of the multilayered mirror is controlled for image formation, from the component guanine crystals at the nanoscale to the complex three-dimensional morphology at the millimeter level. The layered structure of the mirror is tuned to reflect the wavelengths of light penetrating the scallop’s habitat and is tiled with a mosaic of square guanine crystals, which reduces optical aberrations. The mirror forms images on a double-layered retina used for separately imaging the peripheral and central fields of view. The tiled, off-axis mirror of the scallop eye bears a striking resemblance to the segmented mirrors of reflecting telescopes. [ABSTRACT FROM AUTHOR]

A grazing point of a concave mirror illuminated by a large beam of rays is a point of the mirror's edge where the incident ray is parallel to the mirror. In the neighborhood of such point the rays are reflected a great number of times. We show that an ordered series of caustics passes through the grazing point, each caustic corresponding to a fixed number of reflections by the mirror. We study, in the framework of planar geometrical optics, the structure of this remarkable set of caustics. Our main result is a formula giving the curvature of the caustic curves at the grazing point as a function of the number of reflections. This sequence is universal in the sense that it is independent of the shape of the incident wavefront. A grazing point in the plane is an unstable point and we show how the caustic structure is modified under the effect of a small perturbation of the optical system. [ABSTRACT FROM AUTHOR]

This article examines the localization of high frequency electromagnetic fields in three-dimensional axisymmetric cavities along periodic paths between opposing sides of the cavity. When these orbits lead to unstable localized modes they are known as scars. This article treats the case where the opposing sides, or mirrors, are concave, leading to interior foci. Particular attention is focused on the normalization through the electromagnetic energy theorem. Both projections of the field along the scarred orbit, as well as field point statistics, are examined. Statistical comparisons are made with a numerical calculation of the scars run with an axisymmetric simulation. [ABSTRACT FROM PUBLISHER]

The theoretical analysis has been made and the calculations have been performed to define the mechanism of phase conjugation for the case of pump beam self-crossing in the medium active to stimulated Brillouin scattering (SBS) with its reflection back from the focusing mirror. It has been shown that in these circumstances phase conjugation can be realized through nondegenerate Brillouin four-wave mixing with feedback on standing phase gratings. The threshold value of the gain increment of the conjugated wave has been defined. [ABSTRACT FROM AUTHOR]

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We present the fabrication of exceptionally small-radius concave microoptics on fused silica substrates using CO2 laser ablation and subsequent reactive ion etching. The protocol yields on-axis near-Gaussian depressions with a radius of curvature ≲5 μm at shallow depth and low surface roughness of 2Å . This geometry is appealing for cavity quantum electrodynamics where small mode volumes and low scattering losses are desired. We study the optical performance of the structures within a tunable Fabry-Pérot type microcavity and demonstrate near-coating-limited loss rates (F=25 000) and small focal lengths consistent with their geometrical dimensions. [ABSTRACT FROM AUTHOR]

A microelectromechanical systems (MEMS) deformable mirror is described that uses a novel actuation scheme to increase the optical focus range. In this method, electrostatic-pneumatic actuation is used to achieve a convex surface curvature of the mirror with negative focus, while direct electrostatic actuation creates a concave surface with positive focus. Mirrors have demonstrated 20- $\mu $ m total stroke with more than 2-kHz bandwidth. The fabricated device consists of two membranes made of the photoset epoxy SU-8. One membrane serves as the deformable mirror and the other one as the pneumatic actuator. The pneumatic membrane also provides a built-in valve for pressure equalization. The principle of operation, fabrication process, and results are presented. [2014-0135] [ABSTRACT FROM AUTHOR]

A converging electron mirror can be used to compensate for spherical and chromatic aberrations in an electron microscope. This paper presents an analytical solution to a diode (two-electrode) electrostatic mirror including the next term beyond the known hyperbolic shape. The latter is a solution of the Laplace equation to second order in the variables perpendicular to and along the mirror׳s radius ( z 2 − r 2 / 2 ) to which we add a quartic term ( k λ z 4 ). The analytical solution is found in terms of Jacobi cosine-amplitude functions. We find that a mirror less concave than the hyperbolic profile is more sensitive to changes in mirror voltages and the contrary holds for the mirror more concave than the hyperbolic profile. [ABSTRACT FROM AUTHOR]

High-resolution imaging of a dipole source in stratified medium based on negative refraction is presented in this paper. Compensation of the material parameter contrast at the stratified media interface is achieved using a gradient phase profiled conjugating lens (GPCL). It is shown both analytically and numerically that the phase gradient applied across the GPCL positioned at the interface of vertically stratified media enables a high-quality image of a dipole source in a mirror symmetric position with respect to the lens plane. The analytical closed form expression of the phase gradient function is derived using Huygens-Kirchhoff principle. The result is applicable to media with arbitrary stratification and material parameters, including lossy materials. The mechanism for formation of the dipole image in the stratified medium and aberration due to the dielectric contrast at the interface, particularly electromagnetic loss, is discussed in detail. The efficacy of gradient phase and amplitude aberration compensations mechanisms available through the GPCL is articulated. The results of the study are of importance in a wide range of imaging problems in stratified media for medical, civil, and military applications. [ABSTRACT FROM PUBLISHER]

To fully exploit the ultimate source properties of the next-generation light sources, such as free-electron lasers (FELs) and diffraction-limited storage rings (DLSRs), the quality requirements for gratings and reflective synchrotron optics, especially mirrors, have significantly increased. These coherencepreserving optical components for high-brightness sources will feature nanoscopic shape accuracies over macroscopic length scales up to 1000 mm. To enable high efficiency in terms of photon flux, such optics will be coated with application-tailored single or multilayer coatings. Advanced thin-film fabrication of today enables the synthesis of layers on the sub-nanometre precision level over a deposition length of up to 1500 mm. Specifically dedicated metrology instrumentation of comparable accuracy has been developed to characterize such optical elements. Second-generation slope-measuring profilers like the nanometre optical component measuring machine (NOM) at the BESSY-II Optics laboratory allow the inspection of up to 1500 mm-long reflective optical components with an accuracy better than 50 nrad r.m.s. Besides measuring the shape on top of the coated mirror, it is of particular interest to characterize the internal material properties of the mirror coating, which is the domain of X-rays. Layer thickness, density and interface roughness of single and multilayer coatings are investigated by means of X-ray reflectometry. In this publication recent achievements in the field of slope measuring metrology are shown and the characterization of different types of mirror coating demonstrated. Furthermore, upcoming challenges to the inspection of ultra-precise optical components designed to be used in future FEL and DLSR beamlines are discussed. [ABSTRACT FROM AUTHOR]

We report the realization of a device based on a single Nitrogen-Vacancy (NV) center in diamond coupled to a fiber-cavity for use as single photon source (SPS). The device consists of two concave mirrors each directly fabricated on the facets of two optical fibers and a preselected nanodiamond containing a single NV center deposited onto one of these mirrors. Both, cavity in- and out-put are directly fiber-coupled, and the emission wavelength is easily tunable by variation of the separation of the two mirrors with a piezo-electric crystal. By coupling to the cavity, we achieve an increase of the spectral photon rate density by two orders of magnitude compared to free-space emission of the NV center. With this work, we establish a simple all-fiber based SPS with promising prospects for the integration into photonic quantum networks. [ABSTRACT FROM AUTHOR]

This article is a sequel to a previous article dealing with localization of time-harmonic, high-frequency modal fields in a two-dimensional cavity along periodic paths between opposing sides of the cavity. The cases where these paths (or orbits) lead to unstable localized modes are known as scars. In the present article, a stadium-like cavity with concave walls on opposing sides is treated. In contrast to the previous case of a bowtie cavity with convex walls and foci outside the region of consideration, a stadium cavity contains interior foci. [ABSTRACT FROM AUTHOR]

A small-angle neutron scattering instrument that uses a reflective focusing optic can achieve smaller values of the scattering vector, and with higher resolution, than the usual pinhole collimation. When the focusing mirror images the source onto the detector, the analytic expression for the resolution is independent of the sample area and is principally determined by the beam divergence incident on the sample, modified by the distance between the optic and the sample. The results are applied to a focusing SANS instrument with axisymmetric mirrors. [ABSTRACT FROM AUTHOR]

Highlights: [•] A layer of titania semi-spherical shell is assembled onto the titania nano-crystalline film. [•] The shell performs as a concave mirror. [•] Unlike random scattering centers, the unique structure reflects full band incident light back into the photo-anode. [•] Conversion efficiency is enhanced by the semi-spherical shell. [Copyright &y& Elsevier]

Highlights: [•] We describe the detailed design of a high lateral resolution and wide-angle-resolved HAXPES. [•] The lateral resolution with Kirkpatrick–Baez focusing mirrors is achieved 1μm at the photon energy of 7.94keV. [•] Total acceptance angle which we had been developed originally is achieved ±34° with a resolution of 1.32°. [•] This microprobe ARXPS is applied to studies on a buried interface profiles for advance in HAXPES. [ABSTRACT FROM AUTHOR]

Focal shift in radially polarized beam with radial cosine phase wavefront are investigated theoretically by vector diffraction theory. The wavefront phase distribution is cosine function of radial coordinate. Simulation results show that when the radially polarized beam with radial cosine wavefront phase is focused, the focal pattern differs considerably with frequency parameter in the cosine function term. On increasing C, focus can shift along optical axis and focal pattern changes remarkably. Focus may move in different direction under different condition. Focal shift distance fluctuates on increasing C, and fluctuation amplitude also increases simultaneously. In addition, focal shift direction can also be adjusted by changing frequency parameter in cosine function. [ABSTRACT FROM AUTHOR]

The polarisation dependence of integrated concave diffraction gratings with extended metallic or dielectric elliptical Bragg reflectors was investigated. Equal grating efficiency of 99% for both polarisations was achieved for the dielectric configuration using finite-difference time-domain (FDTD) modelling, with a polarisation-dependent loss (PDL) of 0.07 dB. [ABSTRACT FROM PUBLISHER]

Ultraprecise aspheric mirrors that offer nanofocusing and high coherence are indispensable for developing third-generation synchrotron radiation and X-ray free-electron laser sources. In industry, the extreme ultraviolet (wavelength: 13.5 nm) lithography used for high-accuracy aspheric mirrors is a promising technology for fabricating semiconductor devices. In addition, ultraprecise mirrors with a radius of curvature of less than 10 mm are needed in many digital video instruments. We developed a new type of nanoprofiler that traces the normal vector of a mirror's surface. The principle of our measuring method is that the normal vector at each point on the surface is determined by making the incident light beam on the mirror surface and the reflected beam at that point coincide, using two sets of two pairs of goniometers and one linear stage. From the acquired normal vectors and their coordinates, the three-dimensional shape is calculated by a reconstruction algorithm. The characteristics of the measuring method are as follows: the profiler uses the straightness of laser light without using a reference surface. Surfaces of any shape can be measured, and there is no limit on the aperture size. We calibrated this nanoprofiler by considering the system error resulting from the assembly error and encoder scale error, and evaluated the performance at the nanometer scale. We suppressed the effect of random errors by maintaining the temperature in a constant-temperature room within ±0.01°C. We measured a concave spherical mirror with a radius of curvature of 400 mm and a flat mirror and compared the results with those obtained using a Fizeau interferometer. The profiles of the mirrors were consistent within the range of system errors. [ABSTRACT FROM AUTHOR]

A passive scanning imaging system that can operate at multiband spectra covering infrared, THz, and MMW regions has been developed. A high-quality optical system, which consists of a scanning swing planar mirror and a concave mirror, is used to be compatible in different frequency ranges. An elliptical aperture is opened at the center of the swing mirror to allow the focused light to pass through. Four types of detectors that contain two homemade bolometric detectors are used to distinguish images that range from infrared to millimeter waves. Our results demonstrate that the reflection-type imaging system performs well and exhibits compatibility to operate at different frequencies. [ABSTRACT FROM AUTHOR]

Abstract: We started to construct new beam line for neutron spin echo spectrometers (VIN ROSE) at BL06 J- PARC/MLF from FY2011.The advantage of MIEZE is flexible sample environment and polarimetry analysis. The key device of NRSE is focusing mirror and high-m polarizing device. Both spectrometers are to use intensity gain of J-PARC and dedicated for small sample size. In this study, we show conceptional design of the VIN ROSE and current status of the BL06 beam line at J-PARC/MLF. [Copyright &y& Elsevier]

The article offers the author's insights on how Plate Optimizer (PLOP) finite-element analysis developed his fast-light mirror designs. The author notes that PLOP works only with concave or convex mirrors having a flat back but can be deceived using hand waving to evaluate mirrors having curve rear surfaces. He mentions optician Barry Arnold who worked with thin mirrors which made him to finish his mirror and complete the telescope, and the PLOP 3 with Z88 analysis allowing some modifications.

This paper presents a methodology for the sizing of linear Fresnel reflectors with curved mirrors and inverted compound parabolic concentrator cavity. The objective of the paper is to determine the geometrical parameters of the concentrator to obtain the maximum solar energy collection. The proposed methodology uses an analytical procedure in conjunction with a ray trace technique. A parametrical study evaluating the operation hours for a representative day in the critical month for the city of Mexicali, Baja California, Mexico, was carried out. For a concentrator with seven curved mirrors of 34.3 cm width and tubular absorber of 4.2 cm diameter, the resulting dimensions were: 10 cm spacing between mirrors, 1.8 m focal distance and 19.7 cm width cavity. With these dimensions, a geometrical concentration of 11.9 and collection efficiency of 82.4% are obtained. [ABSTRACT FROM AUTHOR]

We present a high resolution, full color, volumetric display. The display utilizes a novel optical element: the large-aperture, rim-driven, adjustable-resonance, varifocal beamsplitter. The display generates volumetric real images with pixel addressable depth planes. The primary image generator is an RGB liquid crystal panel backlit by a highspeed video projector. [ABSTRACT FROM AUTHOR]

Close-range phatogrommetry has been used to control the construction of a jig used in the assembly of a new generation solar concentrator and the validation of the final, mirrored surface. The concentrator is a concave paraboloid dish with an area of a 489 m². The typical photagrammetric relative precision realized was 1:175,000, corresponding to an accuracy of better than 1 mm at the jig reference points. The validation of the mirrored surface achieved a relative precision of 1:300,000. Photogrammetry was also used to characterize the dish mirror panels. The rear surface of the panels was mapped, as it made possible a denser target array and quicker image capture than if the reflective surface was used. The targets were produced with a digital projector, and the typical measurement precision attained was 1:150,000. This paper describes the equipment and techniques required to provide the required accuracy and precision for the jig and panel surfaces. [ABSTRACT FROM AUTHOR]