We present a method for modeling gravitational lensing as gradient-index lenses in the ray-tracing software CODE V. When applied to gravitational lensing by the Sun, these models yield results in agreement with theoretical and experimental results. The extension of this type of model to “lumpy” astronomical objects whose lensing behavior is difficult to predict with traditional methods is discussed.
Scanning confocal Raman microscopy is proposed to measure a gradient index (GRIN) profile at an optical surface. The Raman microscope is calibrated to index of refraction for a binary copolymer GRIN material, and then the index of refraction is mapped on the plano surface of a GRIN polymer lens. The measurement deduces axial shift of 680 μm and identifies lateral tilt or decenter with respect to the nominal position of the GRIN profile. Results suggest that the mapping method is a nondestructive way to measure the GRIN profile of a GRIN lens and its positioning within the lens geometry, to within the sampling precision of the Raman microscope.
A smart glass augmented reality (AR) display system is designed with a streamlined form factor featuring an off-axis mirror design. The main component of the combiner optics is in the shape of a regular pair of eyeglasses or sunglasses, with no diffractive gratings, waveguides (lightguides), prisms or Fresnel surfaces involved. High quality see-through performance is achieved with a low-cost combiner that consists of only highly manufacturable reflective surfaces. The 20-degree full field of view of the AR display is centered at about 30 degrees with respect to the center of the ocular vision. Such a design allows the user to have a clear unobscured central field of view. At the same time, the projected image is accessible by moving the eyeball off the central vision. The system is designed with a circular eye box with more than 10 mm in diameter.
A typical light field virtual reality head-mounted display (VR HMD) is comprised of a lenslet array and a display for each eye. An array of tiled subobjects shown on the display reconstructs the light field through the lenslet array, and the light field is synthesized into one image on the retina. In this paper, we present a novel compact design of binocular spatially multiplexed light field display system for VR HMD. Contrary to the flat lenslet array and flat display used in current light field displays, the proposed design explores the viability of combining a concentric curved lenslet array and curved display with optimized lenslet shape, size and spacing. The design of placing lenslet array on a spherical surface is investigated and the specification tradeoffs are shown. The system displays highest resolution at the direction wherever the eye gazes. The design form is thin and lightweight compared to most other VR optical technologies. Furthermore, the use of a curved display reduces the complexity of optical design and wastes fewer pixels between subobjects. The design simultaneously achieves a wide field of view, high spatial resolution, large eyebox and relatively compact form factor.
There are advantages to using planar light guide (PLG) concentrators instead of Fresnel concentrators for glass building façade photovoltaic systems. This paper details the main components of a PLG concentrator and describes how the concentrator works. The design of a PLG concentrator is constrained by the limitations of the diamond turning process used to make the microlens array. These manufacturing limitations and their effects on the lens design and system performance are reviewed. We report on the design of a 25 × 100 mm planar light guide concentrator with a 50x geometric concentration and an 85.0-88.1% theoretical optical efficiency for use in building integrated photovoltaics.
Surmet continuously strives to develop novel, advanced optical ceramics products for current and future defense and
commercial systems. Using conventional powder processing techniques, Surmet has made substantial progress in its ability
to manufacture large ALON® sensor windows, lenses, domes and transparent armor. In addition to transparency, Surmet
has demonstrated the ability to incorporate other capabilities into its optical ceramic components, including: EMI shielding,
heating, internal antennas and cooling channels.
Working closely with the University of Rochester, Surmet has developed gradient index (GRIN) optics in ALON for
use in the visible through the MWIR applications. Surmet has demonstrated the ability to tailor the refractive index of
ALON® Optical Ceramic by either varying its composition or through the addition of dopants. Smooth axial and radial
gradient profiles with ~0.055 change in refractive index, over depths of 1-8 mm (axial) and over 20 mm radius (radial)
have been demonstrated. Initial design studies have shown that such elements provide unique capabilities. Radial gradients
in particular, with their optical power contribution, provide additional degrees of freedom for color correction in broadband
Surmet continues to mature ALON® GRIN technology along with the associated metrology. Surmet is committed to
the development of its ALON® GRIN capability as well as finding insertion opportunities in novel imaging solutions for
military and other commercial systems.
A design study is compiled for a VIS-SWIR dual band 3X zoom lens. The initial first order design study investigated zoom motion, power in each lens group, and aperture stop location. All designs were constrained to have both the first and last lens groups fixed, with two middle moving groups. The first order solutions were filtered based on zoom motion, performance, and size constraints, and were then modified to thick lens solutions for the SWIR spectrum. Successful solutions in the SWIR were next extended to the VIS-SWIR. The resulting nine solutions are all nearly diffraction limited using either PNNP or PNPZ (“Z” indicating the fourth group has a near-zero power) design forms with two moving groups. Solutions were found with the aperture stop in each of the four lens groups. Fixed f-number solutions exist when the aperture stop is located at the first and last lens groups, while varying f-number solutions occur when it is placed at either of the middle moving groups. Design exploration included trade-offs between parameters such as diameter, overall length, back focal length, number of elements, materials, and performance.
An all-plastic high-performance eyepiece design utilizing a polymer spherical gradient-index optical element is presented. The use of a gradient-index lens in the eyepiece offers better off-axis and chromatic aberration correction, as well as overall performance improvement compared to a similar eyepiece with all homogeneous lenses.
Gradient-index (GRIN) zoom lenses are shown to offer superior imaging performance to homogenous designs over the visible spectrum. For a given element count, copolymer GRIN designs are better corrected for axial and lateral color than homogeneous aspheric designs.
Gradient-index (GRIN) zoom lenses are shown to offer superior imaging performance to homogenous designs over the visible spectrum. For a given element count, copolymer GRIN designs are better corrected for axial and lateral color than homogeneous aspheric designs. A macro was developed in CODE V® to calculate the surface contributions to both axial and lateral color for a radial GRIN lens. This macro confirms the improved color correction of the GRIN systems over the homogeneous ones.
High-performance eyepiece designs have been carried out using both spherical and radial gradient-index (GRIN)
elements. Eyepiece designs of both geometries are shown to offer superior imaging performance with fewer elements
when compared to purely homogeneous systems. These GRIN lenses are formed from monomer diffusion between
polymethyl methacrylate (PMMA) and polystyrene (PSTY) during the polymerization process, resulting in a copolymer
of the two homogeneous materials.
A process for fabricating spherical GRIN elements is discussed where copolymer axial GRIN blanks are thermally
compressed using spherical surface molds. This process curves the nominally-straight isoindicial surfaces of the axial
GRIN rod to be consistent with the shape found during optimization of the design. Once compressed, the spherical
blanks are diamond-turned for final surface figure and finish. Measurement of the GRIN profile is carried out using the
Schmidt immersion technique in a Mach-Zehnder interferometer. Tolerances specific to GRIN elements are identified
and determined to be readily achievable using the aforementioned manufacturing process.
Radial and spherical polymer gradient-index (GRIN) eyepiece designs are presented. The chromatic behavior of GRIN profiles is constrained to real material properties of a polymethyl methacrylate polystyrene copolymer gradient-index system. Single-element, two-element, and multielement eyepiece design configurations each demonstrate significant spot diameter and modulation transfer function performance improvements with the use of a GRIN element. A high-performance spherical GRIN eyepiece design, with 48-deg full field-of-view and 3% distortion, is compared to a similar homogeneous glass solution.
A 40-deg full field-of-view high-performance eyepiece design utilizing a polymer spherical gradient-index (GRIN) optical element is presented. In the design process, the GRIN lens material is constrained to current manufacturing capabilities. Several spherical GRIN lens blanks are fabricated from a thermoformable axial GRIN polymethyl methacrylate polystyrene copolymer material. One is diamond turned into a lens for the eyepiece, and the additional blanks are used to characterize the fabrication process. The spherical GRIN profile is evaluated in the original design, and a tolerance analysis is provided.
The article explores the possibility of athermalizing a gradient-index (GRIN) lens so that the effective focal length (EFL) of the element remains constant over a change in temperature. This is accomplished by designing the lens so that the surface curvatures and index profile compensate for one another over a change in temperature to maintain constant optical power. The means to determine how the lens geometry and index profile change with temperature for both a homogeneous and radial GRIN are explained. An analytic model for the purpose of identifying athermalized GRIN singlets is described and validated against the previous work in this field. The model is used to identify an athermalized polymer radial GRIN element and compare it with four other polymer elements of the same focal length but different index profiles, including a homogeneous one. Comparison of these singlets in CODE V® optical design software shows that the athermalized GRIN element maintains its nominal EFL over a temperature change the best of the five in the group while the homogeneous element (having no GRIN profile to counteract the effect of temperature on the surface curvatures) has the poorest performance. A numerical model to analyze more complicated GRIN systems is discussed.
Fibroblast is the main part in the loose connective tissue and differentiates from the mesenchymal cell when it is in embryo. It exhibits highly reproducible growth kinetics and reproducible healing dynamics in the scratch-wound assay and the height of it could show this prediction. In order to measure the height of these cells, we construct an
interferometer measuration system. As we all know, the interference pattern should be unwrapped first, there are plenty of methods that are under research. In this paper we want to find out a typical methods that could be used in living cell's interference pattern during image processing, and also we can get the conclusion that how to use the method and why it
is fit to unwrap the phase of cells. There are mainly three parts in this paper: Firstly, we have designed an Interference
system which can be used to get the interference pattern, here we used multiphase interference microscope to measure the cell height. Secondly, a typical method which is based on Goldstein's branch cuts algorithm were used to guide the way that how the phase is unwrapped, this method is the most efficient way to phase unwrapping, and it could induct the unwrapping path through using the branch cut method which could get rid of the residues as much as it could be. As a comparison, we also used some other methods to find different results. Such as the quality-guided path following phase unwrapping; and the Costantini phase unwrapping. Finally, we analyzed the results of the three-dimensional model of the
cell surface topography, as a result of the various noises during the experiment, all these unwrapping methods above can't eliminate all the residues and noises, but compared with the other results, the Goldstein's branch cut method has the
fittest advantages, it gives the most fluent topography of the living cells.
This work presents a planar optical light guide design for concentrating solar power onto a photovoltaic cell. The design allows concentrated light injected into the guide to avoid interaction with other injection facets. The presented design has a HFOV of 1°, geometrical concentration of 112.5x at the output of the guide, and can achieve greater than 500x with secondary concentration.
This paper describes the design, assembly, and testing of a concentrating photovoltaic module which uses spectral
splitting to achieve high system power efficiency. The assembly and testing of two prototype modules is also
described. An efficiency of 37.5% was measured on the highest performing module.
In nature, the compound eye is the most common micro optical system. Currently there are few artificial compound
eye designs incorporated into existing technology. Modeling and fabrication of tapered gradient index polymer
lenses are in development for application in a compound array system that operates similar to the neural
superposition eye. An artificial adaptation will have multiple optical channels that all have simultaneous access to a
large field of view.
Gradient index (GRIN) lenses are more common than you may know. The human lens is a gradient index optic, and the last time you scanned a document the scanner probably used a gradient index lens array. In a homogeneous lens, light refracts at the surfaces, only bending when it enters and exits the material. In a GRIN lens, light refracts at the surfaces and also bends inside the lens. The ability of GRIN optics to bend light gives an optical designer more variables to work with and opens up new design spaces. This course is designed to introduce optical designers and engineers to existing and emerging GRIN materials and to teach them the essentials necessary to use GRIN materials in optical designs.
This course begins with an introduction to gradient index phenomenon and the basic principles of GRIN optics. The properties of axial, radial and spherical optical systems will be presented as will a review of aberration theory. A variety of GRIN materials that cover wavelength bands from the visible to the long wave infrared will be discussed. GRIN chromatic properties will be reviewed, and the GRIN Abbe number will be introduced. The course will review software tools written to help optical designers use GRIN materials in their systems along with easy-to-understand examples.