This PDF file contains the front matter associated with SPIE Proceedings Volume 9272, including the Title Page, Copyright information, Table of Contents, Invited Panel Discussion, and Conference Committee listing.

Light scattering caused by imperfections of optical components can critically affect the performance of optical systems in terms of losses and image degradation. Because of the numerous potential sources of scattering such as roughness, surface and sub-surface defects, bulk inhomogeneities, as well as coatings, scattering properties must be carefully specified and measured at the wavelengths of application. Bidirectional Reflectance and Transmittance Distribution Functions (BRDF / BTDF) are used to quantify the angle resolved scattering properties. The data can be used as an input for optical engineering software just as FRED, ASAP, ZEMAX for stray light modeling. In addition, analyzing the scattered light can provide valuable information about the relevant imperfections. The presentation provides an overview of instrumentation for light scattering measurements at wavelengths ranging from the visible to the extreme ultraviolet and the infrared spectral regions. Examples of applications will be discussed ranging from superpolished mirrors to diffraction gratings, interference coatings, and black absorbing coatings.

Laser beam combiners, which can be used for compact projection-type displays, are reviewed and a newly-proposed extremely-small laser beam combiner composed of optical waveguides and optical couplers is described. Here, the laser beams with three RGB (Red-Green-Blue) primary colors are combined into one single beam by using the laser beam combiner. Such combiners are classified into three categories, i.e., a mirror-prism type, an optical-fiber type and an optical-waveguide type. The mirror-prism-type combiners are composed of the mirrors and/or prisms for combining the laser beams. The optical-fiber-type combiners use the optical couplers made of optical fibers. On the other hand, opticalwaveguide- type combiners, which are based on the optical waveguides, are particularly useful because they enable us to construct extremely small laser combiners integrated with laser sources. Here, we proposed and analyzed a new integrated waveguide-type red-green-blue (RGB) beam combiner that can contribute to a miniaturization of the compact projection-type displays such as an eyewear projector. The essential point of this beam combiner is that it is composed of three individual waveguides for RGB light inputs, and three directional couplers. The combined output light can be obtained from the single waveguide. The waveguide supports the single mode transmission. The efficiency for output light is as high as 96%, and the size is as small as 0.06×7.8 mm. In addition, the small dependence of the output efficiency on the wavelength and the relatively large fabrication tolerance are obtained.

With the advantages of low cost, small volume, low energy consumption, long service life and environment friendly, the application of UV-LED has attract widespread concern among academia and industry researchers, especially in the field of ink printing industry. However, how to get high power density in specific distance working plane is a technical problem need to be solved eagerly. This paper presents a design solution to reduce the Etendue of the lighting system and therefore obtain high power density. The design uses UV-LED array as the light source, and uses a freeform surface collimating lens array to collimate this light source. In order to improve the energy sufficiency of the system, multipoint fitting-based freeform surface lens design for UV-LED extended sources is proposed to design collimating free-form lens for UV-LED extended source in this work. The freeform surface collimating lens array is placed in front of the UV-LED extended sources array. And an aspherical lens is used in the optical path to focus the light beam. In the simulation, a light source module with the size of 9mm * 26mm has been designed, and obtained power density up to 8W/cm² in the specific working plane with the working-distance of 3cm. This design is expected to replace the existing mercury lamped-based UV light sources and solve the problem in the application of UV-LED ink printing field.

We propose a light guide plate of an oblique incident light source for a vertical- field-switching blue phase liquid crystal display. The LGP consists of a designed microstructure bottom surface and other specially microstructure top surface. We simulated the LGP of a backlight system by optical software (TraceProTM) and the performance of the BPLCD by liquid crystal software (TechWiz). The result shows that the output rays mainly emit at 59° and the uniformity is 78.84%. The designed applicable light guide plate successfully increase the angles of oblique light source and provide a better uniformity of illumination for a vertical-field-switching blue phase liquid crystal display.

Graphene is an emerging transparent conductor that plays a potential role in organic optoelectronic device. Here we report the fabrication of a polymer light emitting diode employing graphene as anode by solution process. The hydrophobic graphene on PET substrate is modified through interface engineering to obtain a good poly(3,4- ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) wettability, which yields a composite electrode with low sheet resistance, high optical transmittance and high work function. The resulting device exhibits good electroluminescence emission and excellent flexibility, which is attributed to our high quality graphene and satisfying interfacial modification. Such polymer light emitting diode employing this green and smart graphene composite anode will promote the development of organic electroluminescent and photovoltaic devices toward a flexible and wearable era.

In order to achieve a uniform illumination distribution confined to a given rectangular region, a feedback modification strategy is introduced in the design of free-form optical surface. The whole process of this strategy includes two steps: solving the initial structure and feedback process. To solve the initial surface, we first divide the source space along its longitude and latitude direction with uniform angel. Because the energy of each longitude and latitude micro-belt of free-form surface and each corresponding micro-belt on the target plane is equal, the target plane can be divided into grids, and then the mapping relationship of source space and target space is constructed. By using Snell’s Law and tangent plane iterative method, we obtain the coordinates of all grid nodes and an initial free-form surface can be constructed. Afterwards we use specific feedback algorithm to improve the illuminating performance. This method is proved to be efficient, the shape of illumination spot is dramatically improved and the design result is satisfactory.

Optical design for several three-dimensional (3-D) displays based on floating real image formation using optical imaging elements, such as a concave mirror and a micro-mirror array device, are described. A volumetric 3-D image consisting voxels distributed in the air can be generated by moving a floating image with an optical scanner and modulating the image at a high-speed frame rate. In addition, floating multi-view autostereoscopic displays implemented by using a high-frame-rate projector and an optical scanner are described. It is possible to expand the viewing area to 360 degrees around a floating image.

In the 19th century, English physicist Charles Wheatstone discovered stereopsis, the basis for 3D perception. His construction of the first stereoscope established the foundation for stereoscopic 3D imaging. Since then, many optical instruments were influenced by these basic ideas. In recent decades, the advent of digital technologies revolutionized 3D imaging. Powerful readily available sensors and displays combined with efficient pre- or post-processing enable new methods for 3D imaging and applications. This paper draws an arc from basic concepts of 3D imaging to modern digital implementations, highlighting instructive examples from its 175 years of history.

In the field of biology and medicine, observation object of the microscope has been changing from the thin specimen to the thick living tissue. Furthermore, observation of the internal structure of a living tissue is also desired by low invasion. However, the real structure of a phase object with three-dimensional distribution such as a living tissue is difficult to observe, because of the influence of the phase distribution before and behind of observation position. We enabled observation of the internal structure of living tissue without stain, by adding a new function to reduce the influence of phase distribution to our Retardation-Modulated differential interference contrast (RM-DIC) microscope system.

Phase-contrast imaging of living tissues is important for investigating biological structures and functions. The phasecontrast scanning optical microscope using annular illumination and image processing has been developed as a new tool for visualizing phase objects. This microscope has excellent features, such as separate phase and amplitude imaging, reducing multiscattering effects and spherical aberration-free imaging. Using a figure-8-shaped spatial-frequency filter with sign correction in order to extract linear phase-contrast components, we observed the phase-contrast structures of biological tissue samples and evaluated the microscope’s imaging features.

We propose integrated phase-shifting digital holography using statistical approach. In the integrated phase-shifting scheme, the phase shifts are generated by a reference mirror moving with a uniform velocity, and sequential phaseshifted holograms are captured. Therefore, there is no wait time for stabilization, which offers some advantages such as short measurement time, high phase stability and high noise tolerance. The proposed method does not require precise control and calibration of the phase shifter and synchronization between the phase shifter and the digital image sensor. Therefore, the practical digital holography system with high accuracy can be implemented at low cost.

To overcome the accuracy limitation due to the machining error of standard parts in measurement system, a threedimensional coordinate measurement method with subwavelength-aperture-fiber point diffraction interferometer (PDI) is proposed, in which the high-precision measurement standard is obtained from the ideal point-diffracted spherical wavefront instead of standard components. On the basis of the phase distribution demodulated from point-diffraction interference field, high-precision three-dimensional coordinate measurement is realized with numerical iteration optimization algorithm. The subwavelength-aperture fiber is used as point-diffraction source to get precise and highenergy spherical wavefront within high aperture angle range, by which the conflict between diffraction wave angle and energy in traditional PDI can be avoided. Besides, a double-iterative method based on Levenbery-Marquardt algorithm is proposed to realize precise reconstruct three-dimensional coordinate. The analysis shows that the proposed method can reach the measurement precision better than microns within a 200×200×300 (in unit of mm) working volume. This measurement method does not rely on the initial iteration value in numerical coordinate reconstruction, and also has high measurement precision, large measuring range, fast processing speed and preferable anti-noise ability. It is of great practicality for measurement of three-dimensional coordinate and calibration of measurement system.

Recently, interferometric null-testing with computer-generated hologram has been proposed as a non-contact and high precision solution to the freeform optics metrology. However, the interferometry solution owns some typical disadvantages such as the strong sensitivity to the table vibrations or temperature fluctuations, which hinders its usage outside the strictly controlled laboratory conditions. Phase retrieval presents a viable alternative to interferometry for measuring wavefront and can provide a more compact, less expensive, and more stable experimental setup. In this work, we propose a novel solution to freeform metrology based on phase retrieval and computer-generated hologram (CGH). The CGH is designed according to the ray tracing method, so as to compensate the aspheric aberration related to the freeform element. With careful alignment of the CGH and the freeform element in the testing system, several defocused intensity images can be captured for phase retrieval. In this paper the experimental results related to a freeform surface with 18×18mm² rectangular aperture (its peak-to-valley aspherity equals to 193um) are reported, meanwhile, we also have compared them with the measurement results given by the interferometry solution, so as to evaluate the validity of our solution.

A comprehensive polarization aberration function is proposed to evaluate the imaging quality of a perturbed high NA lithographic lens. In this function, the system polarization aberration, i.e. Jones matrix, is decomposed into several basic parts as wavefront aberration, apodization, diattenuation, retardance and rotation by single value decomposition (SVD). The wavefront aberration is described by field-Zernike polynomials (FZP), and the diattenuation, as well as retardance, is described by field-orientation Zernike polynomials (FOZP). The relationship of system polarization aberration with pupil, field and manufacturing errors is established by an approximately analytical equation, which provides a possible way to analyze lens tolerance for polarization aberration.

Fundus camera is a complex optical system for retinal photography, involving illumination and imaging of the retina. Stray light is one of the most significant problems of fundus camera because the retina is so minimally reflective that back reflections from the cornea and any other optical surface are likely to be significantly greater than the light reflected from the retina. To provide maximum illumination to the retina while eliminating back reflections, a novel design of illumination system used in portable fundus camera is proposed. Internal illumination, in which eyepiece is shared by both the illumination system and the imaging system but the condenser and the objective are separated by a beam splitter, is adopted for its high efficiency. To eliminate the strong stray light caused by corneal center and make full use of light energy, the annular stop in conventional illumination systems is replaced by a fiber-coupled, ring-shaped light source that forms an annular beam. Parameters including size and divergence angle of the light source are specially designed. To weaken the stray light, a polarized light source is used, and an analyzer plate is placed after beam splitter in the imaging system. Simulation results show that the illumination uniformity at the fundus exceeds 90%, and the stray light is within 1%. Finally, a proof-of-concept prototype is developed and retinal photos of an ophthalmophantom are captured. The experimental results show that ghost images and stray light have been greatly reduced to a level that professional diagnostic will not be interfered with.

Radially polarized beams have cylindrically symmetric polarization profile. When focused tightly such beam gives rise to a strong axially polarized electric field component at the focus. Owing to this unique property, radially polarized beams have found applications in a number of important areas. There has been published research work on the properties of the radially polarized beam in the presence of primary monochromatic aberrations. However optical system involving such beam may also contain second order aberrations. Unfortunately there has not been any such study in the available literature. In this work we will employ vectorial diffraction theory to investigate the effect of the focal field components due to the presence of second order aberrations.

Nanofabrication is the foundation of nanophotonics and has become a research hotspot in the last decades. The method annealing crack is proposed to transfer the nanocracks from ultraviolet (UV) resist to other photonic materials. The method is demonstrated by simulating the inner stress distribution with the thermal-structure analysis. In addition, the parameter influence to the maximum stress is discussed and the results indicate that the annealing temperature has a large effect. The method is simple, low cost, high efficiency and is a good candidate to fabricate nanophotonic structures with critical size less than 50nm.

The paper has been withdrawn from the SPIE Proceedings at the author’s request.

The optical transfer function (MTF) has been widely used in the design and manufacture of optical system. The area under the MTF curve can show image quality of the optical system directly. However, for a long time, as the evaluation remained at the qualitative level, it has little value in practice. When the author started the research of MTF curve integral calculation method, no related literatures were available. With the aid of the OSLO optical design software, optimized optical system structure and corresponding MTF curve discrete data are obtained by means of iterative optimization with the software. Then, the original MTF curve data are fit by MATLAB software and the integral result of the curve is calculated through the relevant numerical method. With the software programmed by the authors, the subjects planned to be evaluated can be ranked in order of image quality automatically. This method can be used as a criterion for evaluating image quality. Application cases show that the evaluation methodology proposed by author is reliable and can be easily operated. This method is supposed to bring about a new way to evaluate the image quality of optical system with the MTF curve.

In this paper, a light-small hybrid refractive/diffractive eyepiece for HMD is designed, which introduces a multilayer Diffractive Optical Element for the first time. This eyepiece optical system has a 22mm eye relief and 8mm exit pupil with 60° FOV. The multilayer DOE overcomes the difficulties of single-layer DOE and double-layer DOE using in the optical system, and improve the image contrast and the performance significantly due to the diffraction efficiency of the multilayer DOE is lager than 90% in wide waveband and large FOV range. The material of multilayer DOE are FCD1 for first layer, FD6 for second layer, PS for the filler layer. Moreover, the weight of the eyepiece system is only 8g, and the diameter of lens is 16mm. The MTF performance can satisfy the requirement of display with VGA resolution. Besides, the lateral color and distortion are 4.8% and 10μm, respectively. The properties of the helmet eyepiece system are excellent.

This paper presents the optical and lens design for alignment to meet the challenging position specifications. Fabrication of the prototypes and testing results and analysis are also presented. The system components as well as their interaction with each other were simulated with Zemax software and tested in an experimental setup in order to conduct tolerance study and provide specifications for the mechanical fixtures used in the system. The epoxy is used to affix the parts together in a cost effective manner for prototyping. The position accuracy of ±3 μm compared to the golden unit has been achieved.

In order to recognize parts’ pose on Coordinate Measuring Machine (CMM) correctly and fast, based on the translation of CMM, A single camera stereo vision measurement method for feature points’ 3D coordinate on the measured parts is proposed. According to the double cameras stereo vision principle, a image of the part to be measured is captured by A CCD camera, which is driven by CMM along its X or Y axis, on two different position correspondly. Thus, the part’s single camera stereo vision measurement is realized with the proposed image matching method, which is based on the centroid offset of image edge, on two images of the same feature point on the part, and each feature point’s 3D coordinate in the camera coordinate system can be obtained. The measuring system is set up, and the experiment is conducted. The feature point’s coordinate measuring time is 1.818s, and the difference value, which is between feature points’ 3D coordinate calculated with the experiment result and that measured by CMM in the machine coordinate system, is less than 0.3mm. This measuring result can meet parts’ pose real-time recognization requirement on the intelligent CMM, and also show that the method proposed in this paper is feasible.

Line of sight stabilization and control system is widely used in pointing and stabilizing the line of sight of optical sensors. Multi-axis gimbals configurations are commonly used for isolating disturbance from the angular motion of the base where the stabilization platform is mounted. However, in the case of large payload, nonlinear friction and the bandwidth limit of the servo loop can greatly diminish the performance of the whole system. Magnetic actuators, because of their high force per mass capability and non-friction characteristic, are promising means of achieving high-accuracy stabilization. Nevertheless, the gap between magnetic actuators and the payload is very small, which limits the slewing range of the line of sight as well as the angular motion range of the base that can be isolated. A novel two-stage stabilization configuration is developed, which combines multi-axis gimbals configuration and magnetic actuators as well as both of their advantages. At the first stage, a multi-axis gimbals configuration is adopted to isolate the large angular motion of the base while at the second stage magnetic actuators are utilized to perform high-accuracy stabilization. A so-called "stabilizing inside and tracking outside" scheme is carried out to perform two-stage stabilization control. The advantage of this configuration compared with conventional configuration is analyzed through analytical method. Finally, the effectiveness of the design is investigated through simulation studies.

The machine vision system has already become the optical mechanical electrical integration products or components of products in modern equipment manufacturing industry. The new LED is more excellent than the halogen tungsten lamp, laser and other traditional light source. It is used in machine vision system more and more. From the analysis of the functional characteristics, this article pointed out the difference between machine vision LED lighting system and traditional optical instrument lighting system. By the interactive methods which integrate with synthesis design analysis and Simulation, this paper import the element of field flattening theory into traditional lighting design, making it a kind of the new flat field lighting system. The effect when it was applied to high power LED lighting system is good. With the new design concept, through the interactive design method and the new image quality evaluation system, we have a contrast experiment on a kind of LED single lamp lighting system. The results show that the field flat lighting system is superior to the traditional one. The most distinctive feature of the new light system is that, it can improve the performance of critical illumination system in certain procedures -- poor illumination uniformity performance. This new lighting optical structure and the new lighting quality evaluation system have broad prospects.

The key to realize non-moving-element optical zooming lies in VCM (variable curvature mirror). In order to obtain a large optical magnification, VCM should be capable of providing a large center deflection and this requires that the mirror material should be robust enough, require less force to deform and have a high ultimate strength. In this paper, CFRP (carbon-fiber-reinforced-polymer) is selected as the mirror material and a prototype VCM has been fabricated. With diameter of 100mm, thickness of 2mm and initial curvature radius of 1740mm, this VCM can provide a center deflection approaching nearly 23um, which proves the feasibility of CFRP in constructing VCM. Compared with the work reported in [Proc. of SPIE, 8725, 87250W, 2013], the center deflection obtained here becomes even larger.

The ultra-thin imaging system using reflective multiple-fold structure has smaller volume and less weight while maintaining high resolution compared with conventional optical systems. The multi-folded approach can significantly extend focal distance within wide spectral range without incurring chromatic aberrations. In this paper, we present a dual infrared imaging system of four-folded reflection with two air-spaced concentric reflective surfaces. The dual brand IR system has 107mm effective focal length, 0.7NA, ±4° FOV, and 50mm effective aperture with 80mm outer diameter into a 25mm total thickness, which spectral response is 3~12μm.

This paper discusses the optical design of an uncooled dual-band MWIR/LWIR optical system using a circular unobscured three-mirror system which is particularly suitable for wide spectral range , large aperture and small volume imaging systems. The system is designed at focal length 310mm, F-number 1.55 with field of view 1.77°×1.33°. A coaxial three-mirror system is calculated by the paraxial matrix as a starting point. With the condition that the focal point of each conic mirror is placed to coincide successively, elements in the system are tilted and decentered properly to make the system unobscured and the mirrors are arranged to form a round configuration for compactness. The optical path is folded inside the region surrounded by the mirrors. Zernike polynomial surfaces which are limited to be symmetric about tangential plane are used to correct aberrations and to improve the image quality. The modulation transfer function of this system is above 0.65 in MWIR band and above 0.5 in LWIR band all over the field of view at the Nyquist frequency of 20 line pairs per millimeter. The result shows that the space can be utilized efficiently, the system is compact and image quality is favorable.

To overcome some drawbacks of optical system for plane and concave grating typed spectrometer, including serious aberration, worse spectral fatness and low diffraction efficiency etc, a novel optical system based on volume phase holographic transmission (VPHT) grating was designed in this paper. For this grating, its manufacture and theories were investigated, and its diffraction efficiency was numerically simulated. In order to validate this designed optical system, the spectral scaling experiment was performed and the spectral resolution reached 2nm, the calibration equation between the scaling wavelength and corresponding pixels was gotten via linear least square fitting algorithm. It was proved that the wavelength absolute value reach 1.7nm on the wavelength of 635nm, the root-mean-square error (RMSE) of full scaling wavelengths was 0.3nm. These experimental results illustrated that the design of the optical system for spectrometer based on VPHT grating is good.

As the increase of environment and conservation consciousness in recent years, green-lighting concept begins attracting much attention of the people in our country; particularly, the exploration of daylight lighting system is an obvious example. However, in this nature-light lighting system, versatile optical couplers are required to guide and dissipate sunlight into different indoor spaces to produce assistant illumination, and their coupling efficiencies directly affect the whole efficiency of the lighting system. Thus, they play an important role in the daylight lighting system. To obtain high efficient optical couplers, this thesis, other than investigating various used Y-branch couplers, proposes another new type of coupler, which has a positive- or negative-arc Y-branch structure to split a light-beam into two beams or to combine two light-beams into one beam with high efficient light output. From optical simulation results, it can be seen that the output efficiency of this symmetrical Y-branch coupler with positive or negative arc can reach above 90%, no matter it is used as a combiner or splitter. Furthermore, this thesis also goes through an investigation of the Y-branch output field distribution and an improved arc design; the coupling efficiency between the coupler and an externally connected optical fiber can be promoted.

In this paper, an array of blue LEDs with high optical power was presented and discussed. Optical of the novel design was completed with the help of running simulation in TracePro to predict the performance of the module. 36 Cree XP-E blue LEDs with a square reflector were used in the novel design. Optical simulation obtained from TracePro showed that the total optical power of the LED array could reach 16.83W. To verify the simulation results, Aluminum PCB, Copper PCB and Aluminum square reflector have been made respectively. Firstly, 36 Cree XP-E blue LEDs with small-pitch were fixed on each PCB, then; an Aluminum square reflector was assembled on each PCB. This optical module was installed on a radiator and tested. The optical output power of sample 1 used Aluminum PCB and Aluminum reflector and sample 2 used Copper PCB and Aluminum reflector was 8.126W and 9.445W at 2A, respectively. It could be observed that the optical output power of sample 2 was higher than that of sample 1. It could be attributed to the better thermal dispersion performance of Copper. In order to improve the light reflectivity and reduce the loss of light, ultrathin silver was coated on the Aluminum reflector by electron beam evaporation. The optical output power of sample 3 used Copper PCB and silver-plated Aluminum reflector was 12.541W at 2A. A uniform square spot with high optical power was obtained.

Mueller matrix is a useful tool for analyzing polarization characteristics in a wealth of research fields. With Mueller matrix, the modulation effects of samples on polarization could be quantitatively analyzed and discussed. In this paper, all elements in the Mueller matrix are calculated when the lights scatter from one dimensional randomly rough surfaces at different conditions with Kirchhoff approximation method which owns high accuracy and fast calculation speed. Besides, theoretical analysis of the light scattering from randomly rough dielectrics and metal surfaces is also proposed in this paper. Moreover, with both theoretical analysis and numerical simulations, we have explained the variations of all elements in Mueller matrix, more importantly, m₃₄ is highly focused which is quite a significant mark in both randomly rough dielectric and metal surfaces. To our best knowledge, it is the first time this obvious difference is both analyzed and discussed via both theoretical analysis and numerical calculation, and is successfully explained via phase difference between incident and reflective waves. According to the analysis, more information of the target could be obtained in order to determine the characteristics of the target. The paper will be an important reference for polarization imaging in laser radar and remote sensing, etc.

Variable curvature mirror (VCM) is a simplified active optical component being capable of changing its curvature radius. Curvature radius variation within a wide range requires that the VCM should be able to generate a large saggitus variation. Besides that, the surface form accuracy should be maintained above a reasonable level. In this paper, a piezoelectric actuation based prototype VCM is designed, constructed and experimentally tested. The thickness of the K9 plane mirror is only 3mm over the full aperture of 100mm. Six piezoelectric actuators are fixed into a base plate and the head of each actuator is connected to an annular ring through the screw thread. With such a structure, the force provided by each actuator can be transformed to the mirror backside through this annular ring. With each actuator generating the same force, the curvature radius can be changed in a uniform way. At the mean time, the surface form accuracy could be adjusted one point by point to compensation asymmetric modes as well. Mathematical analysis and FEA (finite element analysis) are used together to demonstrate the theoretical correctness. Besides that, the prototype VCM is successfully constructed and experiments have been carried out to give a quantitative assessment on the saggitus variation.

We propose a complementary optimization method to design a freeform lens for uniform illumination with extended LED sources. With this method, a primary freeform lens is first constructed based on a source-target energy mapping approach; then a complementary illuminance on the target plane is introduced to optimize the primary freeform lens so that it can produce uniform illumination with an extended COB LED. The computer simulation results show that the illuminance uniformity of the optimized lens can be improved nearby 30% as compared with that of the primary lens; meanwhile, the optical efficiency achieves above 94%.

We propose a novel design of panoramic annular lenses (PAL) for the imaging of 360° surroundings with a large field of view (FOV) ranging from 30°~105°, which can partly realize the zooming function. Its wavelength band is between 486 and 656 nanometers. The conventional vari-focal PAL is based on the axial shift of some optical components, which will make the blind zone larger and out of the sensing area, while our design is based on the lateral shift, which can make some imaging area zoom in, keep the area of blind zone stay the same, and minimize the whole scale of this system. In order to change the focal length of conventional PAL system, we introduce several pairs of free-form surfaces (Alvarez surfaces) which can be regarded as several plano-spherical lenses and change the focal power of the whole optical system. As we set two different configurations (long focal length and wide angle), all of the optical parameters are designed and optimized with the help of the software (Zemax).

In this paper, the effect of environmental temperature change on multilayer diffractive optical elements (MLDOEs) is evaluated from the viewpoint of the diffraction efficiency and the polychromatic integral diffraction efficiency (PIDE). As environmental temperature changes, the microstructure heights of MLDOEs expand or contract, and refractive indices of substrate materials also change. Based on the changes in microstructure height and substrate material index with environmental temperature, the theoretical relation between diffraction efficiency of MLDOEs and environmental temperature is deduced. A practical 3-5μm Mid-wave infrared (MWIR) optical system designed with a MLDOE, which made of ZNSE and GE, is discussed to illustrate the influence of environmental temperature change. The result shows that diffraction efficiency reduction is no more than 85% and PIDE reduction is less than 50% when environmental temperature ranges from -20°C to 60°C. According to the calculated diffraction efficiency in different environmental temperatures, the MTF of hybrid optical system is modified and the modified MTF curve is compared with the original MTF curve. Although the hybrid optical system achieved passive athermalization in above environmental temperature range, the modified MTF curve also remarkably decline in environmental temperature extremes after the consideration of diffraction efficiency change of MLDOE. It is indicated that the image quality of hybrid optical system with ZNSE-GE MLDOE is significantly sensitive to environmental temperature change. The analysis result can be used for optical engineering design with MLDOEs in MWIR.

Membrane mirror with flexible polymer film substrate is a new-concept ultra lightweight mirror for space applications. Compared with traditional mirrors, membrane mirror has the advantages of lightweight, folding and deployable, low cost and etc. Due to the surface shape of flexible membrane mirror is easy to deviate from the design surface shape, it will bring wavefront aberration to the optical system. In order to solve this problem, a method of membrane mirror wavefront aberration correction based on the liquid crystal spatial light modulator (LCSLM) will be studied in this paper. The wavefront aberration correction principle of LCSLM is described and the phase modulation property of a LCSLM is measured and analyzed firstly. Then the membrane mirror wavefront aberration correction system is designed and established according to the optical properties of a membrane mirror. The LCSLM and a Hartmann-Shack sensor are used as a wavefront corrector and a wavefront detector, respectively. The detected wavefront aberration is calculated and converted into voltage value on LCSLM for the mirror wavefront aberration correction by programming in Matlab. When in experiment, the wavefront aberration of a glass plane mirror with a diameter of 70 mm is measured and corrected for verifying the feasibility of the experiment system and the correctness of the program. The PV value and RMS value of distorted wavefront are reduced and near diffraction limited optical performance is achieved. On this basis, the wavefront aberration of the aperture center Φ25 mm in a membrane mirror with a diameter of 200 mm is corrected and the errors are analyzed. It provides a means of correcting the wavefront aberration of membrane mirror.

Lateral shearing interferometry was an attractive technique to measure the wavefront aberration of high numerical aperture microscope objective lens. A two-dimension lateral shearing interferometer based on chessboard grating was designed for microscope objective wavefront metrology. By positioning the chessboard grating at the Talbot distance of the objective focal plane, the wavefront was divided and sheared in two-dimension. By applying two-dimensional Fourier transform method and differential Zernike polynomial fitting, Zernike coefficients of the wavefront were obtained. A 10x, NA0.25 microscope objective was measured at 632.8nm wavelength, the results showed that the wavefront of the objective was 0.755λ PV, 0.172λ RMS, the repeatability(3σ) of RMS at random grating position was 2.3mλ, the repeatability(3σ) of Z5 to Z36 at random grating position were better than 17mλ.

We present theoretical and experimentally study on performance of typical FEC codes in wireless ultraviolet communication system. The results show that, the communication distance increases about 116% with LDPC and 41% with RS code by comparison with that without FEC.

As in fisheye lens, panoramic annular lens (PAL) has a big barrel distortion due to its large field of view. That has an apparent effect to its imaging performance such as pixel utilization and image resolution. If we manage to control the barrel distortion instead of only increasing it, the resulting system can gain better performance. In this paper we propose a method to control distortion that using Q-type aspheres. First, the Q-type aspheric polynomials and its advantages are introduced in the aspect of algorithm and fabrication relative to the traditional symmetrical polynomial-based aspheres. Then, an example design of PAL with Q-type aspheres using ZEMAX optical design package is presented. The designed PAL’s focal length is -1.25mm, F Number is about 5, distortion in all the fields of view are less than 1% under the f-θ distortion formation. The imaging quality of the optical system approached to diffraction limit. The result shows that Q-type aspheres has certain advantage in distortion control for PAL that can enhance imaging performance.

Fringe test is the method which can detect the relative optical path difference in optical synthetic aperture telescope array. To get to the interference fringes, the two beams of light in the meeting point must be within the coherence length. Step scanning method is within its coherence length, selecting a specific step, changing one-way’s optical path of both by changing position of micro displacement actuator. At the same time, every fringe pattern can be recorded. The process of fringe patterns is from appearing to clear to disappearing. Firstly, a particular pixel is selected. Then, we keep tract of the intensity of every picture in the same position. From the intensity change, the best position of relative optical path difference can be made sure. The best position of relative optical path difference is also the position of the clearest fringe. The wavelength of the infrared source is 1290nm and the bandwidth is 63.6nm. In this experiment, the coherence length of infrared source is detected by cube reflection experiment. The coherence length is 30μm by data collection and data processing, and that result of 30μm is less different from the 26μm of theoretical calculated. In order to further test the relative optical path of optical synthetic aperture using step scanning method, the infrared source is placed into optical route of optical synthesis aperture telescope double aperture. The precision position of actuator can be obtained when the fringe is the clearest. By the experiment, we found that the actuating step affects the degree of precision of equivalent optical path. The smaller step size, the more accurate position. But the smaller the step length, means that more steps within the coherence length measurement and the longer time.

In order to enhance the performance of adaptive optics image restoration, a novel wavefront reconstruction algorithm was presented that was based on generalized ridge estimation.

An azimuthally polarized beam when passes through a helical phase mask, gives rise to a circularly symmetric focal spot which appears very similar to the focal spot of normal linearly polarized beam with a plane wavefront. However it is noticed that common monochromatic aberrations have different degree of influence on the two types of beams, that is the azimuthally polarized beam with a helical phase mask and linearly polarized beam with a plane wavefront. In this paper we present a detailed investigation on the effect of primary aberrations on the two types of vector beams.

Visible Light Communications (VLC) has become an emerging area of research since it can provide higher data transmission speed and wider bandwidth. The white LEDs are very important components of the VLC system, because it has the advantages of higher brightness, lower power consumption, and a longer lifetime. More importantly, their intensity and color are modulatable. Besides the light source, the optical antenna system also plays a very important role in the VLC system since it determines the optical gain, effective working area and transmission rate of the VLC system. In this paper, we propose to design an ultra-thin and multiple channels optical antenna system by tiling multiple off-axis lenses, each of which consists of two reflective and two refractive freeform surfaces. The tiling of multiple systems and detectors but with different band filters makes it possible to design a wavelength division multiplexing VLC system to highly improve the system capacity. The field of view of the designed antenna system is 30°, the entrance pupil diameter is 1.5mm, and the thickness of the system is under 4mm. The design methods are presented and the results are discussed in the last section of this paper. Besides the optical gain is analyzed and calculated. The antenna system can be tiled up to four channels but without the increase of thickness.

We numerically study the splitting of light beam which carries orbital angular momentum (OAM) through single metal nano-scale hole. A light beam carrying with OAM has a helical phase distribution in the transverse plane, where the electric field has the form: E(r,θ)=E₀exp(lθ), and l is the topological charge which denotes the value of OAM. The circular polarization state is corresponding to the spin angular momentum (SAM), where s=+1 represents the left-handed polarization and s=-1 the right-handed polarization. Simulation results show l dependent splitting of beam through nano metal hole. When l is odd, the transmitted far field splits while no splitting happens when l is even. This phenomenon is attributed to the interaction between OAM beam and plasmonic mode of metal nano-hole. It is revealed that different OAM beam can excite different transverse mode in the metal cavity, which means the interaction should obey an OAM section rule. We show that even l can excite transverse mode with zero total AM and odd l can excite transverse mode with non-zero total AM within the hole. Orbital-spin conversion is also revealed in the free wave/plasmon interaction.

A novel method for generating cylindrical vector beams with radial and azimuthal polarization is presented. We use the inner wall waveguide fiber which is a hollow annular symmetry waveguide with air layer, core layer and cladding layer. We plate on its inner wall surface with a suitable thickness and thin silver film. The incident light will be absorbed and polarized in the film area and TE mode will be loss retained TM mode. The experiments results demonstrate that the output optical field distribution is cylindrical vector beams in far field. This method has advantages of simple structure, convenient operation and low cost.

The optical power distribution and the symmetry of the lens components are two important attributes that decide the ultimate lens performance and characteristics. Lens form parameters W and S are the key criteria describing the two attributes mentioned above. Lens components with smaller W and S will have a good nature of aberration balance and perform well in providing good image quality. Applying the Gaussian brackets, the two lens form parameters and the Seidel Aberration Coefficients are reconstructed. An initial lens structure can be analytically described by simultaneous equations of Seidel Aberration Coefficients and third-order aberration theory. Adding the constraints of parameters W and S in the solving process, a solution with a proper image quality and aberration distribution is achieved. The optical properties and image quality of the system based on the parameters W and S are also analyzed in this article. In the method, the aberration distribution can be controlled to some extent in the beginning of design, so that we can reduce some workload of optimization later.

A special kind of metal nanograting which has excellent performance on polarization state controlling, is fabricated by means of interference lithography, reactive ion etching (RIE) and two-time-evaporation coating with metal. The MNG can produce angle-free elliptically polarized light via rolling the direction of grating, so it will have wide and convenient applications in the systems which need flexible polarization orientation. We fabricate the MNG and test its performances on polarization state controlling, then we simulate the process with software.

Catering to the active demand of the miniaturization of spectrometers, a simple microspectrometer with small size and light weight is presented in this paper. The presented microspectrometer is a typical filter-based spectrometer using the extraordinary optical transmission property of subwavelength metal hole array structure. Different subwavelength metal nanohole arrays are designed to work as different filter units obtained by changing the lattice parameters. By processing the filter spectra with a unique algorithm based on sparse representation, the proposed spectrometer is demonstrated to have the capability of high spectral resolution and accuracy. Benefit for the thin filmed feature, the microspectrometer is expected to find its application in integrated optical systems.

Monochromatic energy multilayer Kirkpatrick-Baez microscope is one of key diagnostic tools for researches on inertial confinement fusion. It is composed by two orthogonal concave spherical mirrors with small curvature and aperture, and produce the image of an object by collecting X-rays in each orthogonal direction, independently. Accurate measurement of radius of curvature of concave spherical mirrors is very important to achieve its design optical properties including imaging quality, optical throughput and energy resolution. However, it is difficult to measure the radius of curvature of spherical optical surfaces with small curvature and aperture by conventional methods, for the produced reflective intensity of glass is too low to correctly test. In this paper, we propose an improved measuring method of optical profiler to accomplish accurate measurement of radius of curvature of spherical optical surfaces with small curvature and aperture used in the monochromatic energy multilayer Kirkpatrick-Baez microscope. Firstly, we use a standard super-smooth optical flat to calibrate reference mirror before each experiment. Following, deviation of central position between measurement area and interference pattern is corrected by the theory of Newton’s rings, and the zero-order fringe position is derived from the principle of interference in which surface roughness has minimum values in the position of zero light path difference. Measured results by optical profiler show the low relative errors and high repeatability. Eventually, an imaging experiment of monochromatic energy multilayer Kirkpatrick-Baez microscope determines the measurement accuracy of radius of curvature.

X-ray Timing and Polarization (XTP) satellite with focusing optics and advanced detectors will study Black Hole, Neutron Star, Quark Star and the physics under extreme gravity, density and magnetism. XTP is about to make the most sensitive temporal and polarization observations with good energy resolution in 1-30 keV. We present the design of XTP Telescope with a larger field of view in this paper. The initial structure design of nested conical Wolter-I telescope in X-rays is determined with the focal length f=4.5m, mirror length L=100mm, thickness t=0.3mm, inner and outer diameter D_in-out=100-450mm. To optimize the structure parameters, a self-complied Matlab software is used to maximize the center geometrical collecting are. A constant deviation gap between every two mirrors is introduced, and we calculate geometrical area in on-axis and off-axis. Balancing the performance of the telescope, the final gap value is 0.06 mm. The geometrical collecting area of on-axis decreased by 5%, the average geometrical area of off-axis is increased about 1.7% and the field of view is improved from 22’ to 24’, meanwhile, number of mirrors and total weight of mirrors also are decreased by 5.8%, 5.3% respectively.

Organic solar cells show a commercially viable future duo to their inherent advantages, such as light weight, flexibility, and so on. Recently, a lot of progress has been made in every domain of organic solar cells. Among these, plasmonic light trapping is regarded as a promising light management technology for improving the light absorption in organic active layer. In this work, we numerically investigate the light enhancement in organic solar cell by embedding metal gratings as electrodes, including the anode and cathode. The absorption enhancement mechanism is analyzed, and the effects of grating parameters and incident angle are also investigated systematically. The results show the plasmonic gratings, especially the bottom grating, have an obvious improvement for light harvesting in organic layer, and an optical enhancement factor about 100% is obtained.

Ultraviolet (UV) spectrum of 200nm-300nm from the sun is absorbed by the ozone layer around the earth, which forms the solar-blind spectral region near the ground. Within this spectral region, UV signal interference will be very small. By the characteristics of solar-blind spectral region, it can be used in the fields such as prevention of forest fires, missile approach warning etc. An optical system with FOV 46° is designed for missile approach warning in this paper. To enhance the FOV enlarge the aperture and improve the image quality, two aspheric surfaces and one binary element are adopted in the optical system. PIXIS2048BUV-type camera is selected as the detector of the system, which has pixel size 13.5μm x 13.5μm and imaging area 27.6mm x 27.6mm. After optimization, the RMS radius for maximum FOV is 18μm, which is slightly larger than one pixel size. For other FOV, the RMS radius are all much less than the pixel size. From the encircled energy curve, over 80% of the energy from the object is converged within the circle of radius 6.5μm. Point spread function of each FOV is high enough, which shows the designed optical system has good convergent degree of energy as an energy system.

The research studies a new LED portable desk lamp with V-groove cells light guide plate (LGP). Such LGP enables light of edge LED to be transmitted from the LGP with high efficiency and uniformity to enter a lighting area. Here, the so called V-groove cell is a unit composed of multiple V-grooves we provided, which may regulate light effectively with appropriate design to implement the design goal of lighting. We analyze the impact of V-grooves parameters on LGP, and further, use portable DL as an example to search for suitable V-groove units, and acquire successfully a set of LGP with high efficiency, high illuminance uniformity, and low direct glare. Compared to the commercially available DL, the efficiency is increased by 1.4 times, and the illuminance distribution of target area is similar. Obviously, such microstructure unit composed of multiple V-groove microstructure (VGM) cells can implement design goal of LED portable DL with high efficiency.

When starlight navigation method is applied in the hypersonic vehicle, the complex turbulence generated around the window of star sensor causes starlight deflection, thus lead to the centroid offset of navigation star in the star-map imaging. Starting from characteristics of the flow field, the deflection effects of starlight transmission are researched to solve. At first, based on Reynolds average, the model of flow around the window was established to obtain the density distribution that can be divided into mean-time and fluctuation flow field to analyze the whole field. On this basis, the starlight is traced by using the Runge-Kutta method, while taking the principle of refraction, the evaluation index for starlight deflection is derived to characterize the deflection effect of the field. Finally, verify the applicability of the evaluation index through comparative analysis and also study the impact on deflection effect with the follow situations: different installation locations of star sensor, different angles of incident ray, different Mach numbers and wavelengths of starlight. The study provides the predictive information for centroid offset of navigation star in star-map pre processing to improve the efficiency of star-map matching, and also provides the best choice for the work of the star sensor.

Wavefront sensing and reconstruction finds numerous applications in the field of optical technology. Zonal estimation from the wavefront difference or slope data is an important wavefront reconstruction approach. In this reconstruction method, the wavefront is estimated at specific grid points directly from the wavefront differences by using the least-square method. One of the important sources of error in wavefront estimation process is the detector or CCD centroiding error which may propagate in a basic wavefront estimation process, thereby degrading the performance of the wavefront sensor. Hence, quantification of this error is important as this may be considered as one of the selection parameter of a particular estimation geometry. In the present work, we compute the wavefront difference based (WFDB) error propagation coefficient due to this centroiding error for an improved zonal phase-gradient model which is formally applicable for a Shack-Hartmann (S-H) type sensor and show that the improved model offers a substantial reduction of error propagation. The theoretical error propagation coefficient is shown to have a strong correlation with the experimentally obtained RMS errors for the same model.

The model of the wall washer lamp and the practical illumination application have been established with a new design of the lens to meet the uniform illumination demand for wall washer lamp based on the Lambertian light sources. Our secondary optical design of freeform surface lens to LED wall washer lamp based on the conservation law of energy and Snell’s law can improve the lighting effects as a uniform illumination. With the relationship between the surface of the lens and the surface of the target, a great number of discrete points of the freeform profile curve were obtained through the iterative method. After importing the data into our modeling program, the optical entity was obtained. Finally, to verify the feasibility of the algorithm, the model was simulated by specialized software, with both the LED Lambertian point source and LED panel source model.

General contact between all kinds of image sensor has been noticed. Inspired to in order to reveal the structure to improve imaging resolution, further technical requirement is proposed in some areas of the function and influence on the development of multiple sensors . Based on the comprehensive fundamental theories to close to the diffraction limit, and so that to breakthrough diffraction limit, some correlative methods is studied, the core technology of such a system are thoroughly analyzed.

Polarized illumination and source mask optimization (SMO) are two prominent resolution enhancement technologies (RETs) in immersion lithography. Recently, source-mask-polarization optimization (SMPO) has been developed to support photolithographic process shrinks, which shows that the illumination system with arbitrary intensity and polarization distribution of light in the pupil is emergency. In this paper, we propose a unique illumination system design to match the target SMPO source and meet the requirement of immersion lithography at 45-16 nm node. In our designed illumination system, the adjustable λ/2 wave plates and mirror array are introduced to produce arbitrary intensity and polarization distribution of light in the pupil. The three λ/2 wave plates are designed to that can move freely in certain planes perpendicular to the optical path. To produce target SMPO sources, the positions of thousands spots reflected by adjustable mirrors array are firstly designed and optimized to approximate the target intensity distribution in the pupil corresponding to unpolarized light. Then the target polarization states in all the spots are obtained in the pupil by designing and optimizing the relative positions of the three wave plates. Compared with prior design method, our design results show that the intensity distribution and polarization state of all spots in the pupil match the target SMPO source accurately and efficiently with lower intensity lost.