This PDF file contains the front matter associated with SPIE Proceedings Volume 11548, including the Title Page, Copyright Information, and Table of Contents.

Two phase imaging methods with transport of intensity equation (TIE) under a low signal to noise ratio (SNR) are introduced. One is a TIE phase imaging with deep learning. It is useful for parallel TIE using a diffractive optics to produce defocus images simultaneously. The defocus images are obtained by an optical convolution integral by the calculated blurred point spread functions. However the point spread functions are different from the ideals due to the limited extent and/or limited resolution of the diffractive optics. This means that an SNR of the through-focus images is low. Therefore, deep learning compensates the error. Another is transport-of- intensity computational ghost imaging (TI-CGI). It is a combination of TIE and a computational ghost imaging (CGI). It is useful for noninvasive imaging for the biomedical field because most cells are photo-sensitive and often suffer from phototoxicity. However, CGI can obtain only amplitude information. In the biomedical field, a phase information is important to know the physical parameters. To achieve, under weak illumination, it is difficult to obtain through-focus images with high SNRs. Therefore, combination of TIE and CGI is useful.

When vision is provided through thermal-imaging systems field-of-view is reduced, effectively the soldier must operate with severe tunnel vision and so there is a requirement for a system which provides automated warning and immersive imaging. We present a computational multi-aperture thermal infrared (MA-TIR) imaging system with single-photon range imaging to provide enhanced video-rate detection of obscured biological signatures in clutter. Our multi-camera computational imaging system creates a 360° panoramic image, and we employ synthetic baseline integral imaging (SBII) for the construction of three-dimensional thermal scenes, including detection of occluded objects. We further fuse thermal imaging with covert time-correlated single-photon counting (TCSPC) LIDAR to provide the complementary capability of video-rate ranging with the ability to detect and classify targets through clutter, particularly based on movement signatures. Finally, we demonstrate the ability to discriminate between biological scene components and static clutter based on temporal modulations of picosecond resolution TCSPC returns.

In this work, we evaluate quantitatively the three-dimensional fluorescence imaging based transport of intensity equation (TIE). In the TIE-based fluorescence imaging, phase information from the recorded defocus fluorescence images is retrieved by solving the phase retrieval algorithm. From the retrieved phase data and their corresponding fluorescence image, the complex function can reconstructed. Focus images at different distances can be obtained after applying numerical inverse Fresnel propagation of complex function. For the quantitative evaluation of retrieved focus images, we calculate cross correlation coefficients to check intensity conservation.

In the Multi-intensities phase retrieval processing, the measurement uncertainty of the defocus distance undermines its measurement accuracy. In this paper, using a general phase retrieval experimental arrangement, we propose an adaptive autofocusing nonlinear optimization phase retrieval algorithm based on the extended Nijboer-Zernike (ENZ) theory. This method concurrently accomplishes correction of defocusing position error and the wavefront measurement requiring without additional facility. The numerical experiments show that the proposed method accuracy searching for the optimal defocusing position is superior to 10 μm among different measurement planes. The numerical experiments show that the wavefront measurement accuracy with the proposed method is superior to λ/100 , RMSE.

All optical systems are affected by aberrations, and optical encryption systems with lens are no exception. In order to improve the practicality of the optical encryption system, the influences of aberration on the double random phase encoding (DRPE) system are studied. In this paper, Zernike polynomials are used to express the aberration of the lens. Simulation has been carried out. The influences of different types, coefficients, and combinations of aberrations on DRPE system are analyzed. The results of the study indicate that some Zernike polynomials(such as the 4th Zernike polynomial, etc.)will have a greater impact on DRPE system, while some combinations, such as the combination of the 4th and 9th Zernike polynomials, will reduce the influences of aberrations on DRPE system. Besides, the degree to which DRPE system is affected by aberrations is evaluated by the correlation coefficient between the decrypted image and the plaintext. In order to solve the problem of aberration, two solutions are proposed.

This paper presents the use of dual band anti-reflection (AR) black coatings in reducing stray light effect on Infra Red (IR) camera system sharing aperture. This MWIR and LWIR bands analyses basically deal with the fabricator's perspective, either from the optical or thermal views. Using Thermal Desktop / Sinda Fluint the all processes finally are enclosed. Intending to provide the best black coating that meet all requirements, the first trade-off was involving absorbtivity / low reflectance, low outgassing, low cost, and easy to bond on all substrates as the requirements. Meanwhile, high efficiency, durability (space environment including humidity), and transmission were used as the requisites in the second trade-off process. Moving forward to next step, determining in term of single or dual band was become the concern based on the final result of the second trade analysis. The processes, then, was enclosed using Thermal Desktop / Sinda Fluint to show up the behavior of selected coating material in orbit. Throughout the all analysis, all current AR coatings for infrared were involved in including a new black coating material, acktar. In addition, lens material used was according to our published research previously. According to the whole process, the results of 3 - 4 µm and 8 - 12 µm bands, graphs and tables (numerical data), show that acktar material usage as optical dual band AR black coatings of LAPAN's IR camera equipped with two microbolometer is very useful to reduce stray light effect. Meanwhile in term of performance, It can be said that it provides high performance of both sensor bands. As this is not only focused on making certain existing surface black, the further analysis is still needed to strengthen the output.

Freeform imaging systems have become prevalent given modern advances in design and fabrication capabilities. Many applications requiring compact optical systems, with fewer surfaces and high quality imaging performance have increased demand for flexible modeling and optimization of freeform designs. This paper shows the results of an examination of the optical design optimization convergence for some reflective systems using unique degrees of freedom in modern commercial optical design software. These optimization degrees of freedom offer support for the creation of new system geometries and positively impact the efficiency of the optical design workflow.

Metasurface optical elements such as metalenses have drawn great attentions for their capabilities of manipulating wavefront versatilely and miniaturizing traditional optical devices into ultrathin counterparts, and multi-functional metasurfaces such as bifocal metalenses have attracted tremendous interests due to their potential in system integration. In this paper, an approach to design polarization-dependent bifocal metalenses which are able to independently generate longitudinally or transversely bifocal spots under the incidence of circularly polarized light with arbitrary ellipticity is proposed and demonstrated by full-wave simulations. When the designed devices are illuminated with elliptically polarized lights at wavelength of 532 nm, both of the helicity-multiplexed bifocal spots appear simultaneously, and the relative intensity of both focal spots can be tuned in terms of the ellipticity of the polarization state. In addition, a polarization-independent metalens based on geometric phase modulation is illustrated and the focusing efficiency of it maintains stable ignoring the polarization state of the incident waves, which could be of vital importance in real applications. This design is of enormous potential of being applied in real compact optical systems such as imaging, display, microscopy, tomography, optical data storage and so on.

Optical schemes of aplanatic and afocal compensators of surface curvature and astigmatism are considered. The way of calculation of this kind of compensators and an example of using a doublet lens with an enlarged field with one of it are given.

The imaging x-ray telescope (IXT) has been developed for over a decade at the Institute of Precision Optical Engineering of Tongji University. Since then, we have made great progress on the development of mirror fabrication, coatings, and optic assembly. In this paper, we intend to provide an overview of the progress. Currently, we can routinely produce cylindrical mirror substrates with angular resolution of 16″ to 35″. To improve the effective area, coatings using C, Ni, and Pt layers were designed and achieved a high reflectivity at 0.5 to 10 keV. During the optic assembly, an in-situ measurement system and a three-dimensional ray-tracing program have been developed to guide the assembly process in real time. Several prototypes have been calibrated at the MPE PANTER x-ray test facility in Germany. An IXT prototype with 21 layers was calibrated at the PANTER X-ray test facility, indicating an HPD of 111″ and effective area of 39 cm² at 1.49 keV in August 2018. Now the latest prototype with 3 layers was calibrated indicating an HPD of 58″ at 1.49 keV in September 2019.

The traditional vehicle-mounted augmented reality head-up display system is limited by the large size of the optical lens. The space when installed in the car is very limited. This paper proposes an optical waveguide structure based on multiarea reflective microprism for use in a vehicle-mounted augmented reality head-up display system, which can adapt to the narrow installation space of the dashboard area in the vehicle. The input coupling end of the waveguide structure adopts a transflective film with a specific beam splitting ratio placed obliquely instead of a flat mirror, where the transmitted light beam through the transflective film directly enters the exit pupil, which can reduce the use of a microprism structures and reduce the volume of the waveguide. The reflected light beams continue to propagate in the horizontal and vertical waveguides in sequence, and are coupled out through the right-angle triangular prism array microprism structure with different duty ratios to achieve a two-dimensional exit pupil expansion. Through theoretical calculation and simulation optimization, the results show that when the field of view is 10°×5°, the uniformity of illuminance on the exit pupil within the eyebox range of 140mm×60mm reaches more than 70%, the horizontal waveguide size is 324mm×37mm×30mm, and the vertical waveguide size is 324mm×146mm×12mm, and the head-up display system volume is less than 4L, which has great potential for in-vehicle applications.

The optical combiner is an important part of the optical see-through augmented reality display system. Waveguide is an appropriate solution due to its advantages such as light weight and compact structure. Because grating has replicability, it is a promising solution to the waveguide’s coupler for mass-production. In this paper, a grating coupler for waveguide is designed by using the rigorous coupled wave analysis (RCWA) to increase the accuracy of the simulation due to the critical dimension is similar to the wavelength. The uniformity of the diffraction efficiency is considered as an important parameter for a better displaying performance. The downhill algorithm is used to optimize the parameters of the grating. In order to obtain a large field of view, the thickness of the grating should be controlled carefully. Finally, two gratings are designed for the waveguide which can extend pupil horizontally. The displaying performance of the waveguide is simulated, and the grating couplers are fabricated by the nanoimprint lithography method. The characteristics of the gratings are tested such as transmittance and diffraction efficiency. The results show the proposed gratings can be utilized for waveguide’s coupler. It is believed that our results will give a better alternative for the augmented reality display system.

We developed a hybrid optical headlamp in which LEDs and blue laser diode were properly controlled to maximize a level of 1.5 lx on road. In optical design, we simplified laser phosphorescence model for realizing white light by using Gaussian cross-sectional beam. We simulated various optical systems to capture the focal position and selected the optimized position on simulation. Ray tracing simulation results fulfill the ECE-R112 regulation.

Analyze the source of stray radiation of the geosynchronous infrared telescope system, and list the methods of suppressing infrared stray radiation. The method of setting the internal optical components ‘field stop heat dissipator’ to suppress the stray radiation of the geosynchronous orbit infrared telescope system. Explain the necessity of using heat dissipator and optimize the internal optical and mechanical structure of the telescope system. Use LightTools software to build a model of the infrared telescope system and perform ray tracing analysis, calculate and compare the point source transmittance (PST) value of the infrared telescope system before and after the suppression measures are taken, and evaluate the effectiveness of the stray radiation suppression measures.

It is a meaningful but challenging issue that designing illumination optics for extended sources directly. A number of direct design methods developed specifically to deal with prescribed intensity designs usually fail to produce satisfactory illumination in the near field where the influence of lens size on the irradiance distribution cannot be ignored. In this paper, a direct method of designing aspherical lenses for extended sources is introduced to achieve specified irradiance characteristics. And various types of prescribed irradiance distributions are shown in this paper to verify the broad applicability and high efficiency of the direct design method, especially two examples of producing discontinuous irradiance distributions are analyzed in detail.

This study proposed 1st optical design for wide angle micro LED without 2nd lens. Micro LEDs are point light sources that the beam angle of 120°, therefore, a large number of LEDs are needed to achieve a uniform area light source. We used 1st optical design to modulate luminous intensity curve, in which micro LED as chip and through chip scale packaging (CSP) process to design wide angle micro LED that achieve full width at half maximum (FWHM) of 180°. The prototype used a square packaged that with a flip chip. Chip length, width and height of 240um, 130um and 80um respectively, the structure of wide angle micro-LEDs is including flip chip as light source, side wall around chip, a light guide layer, and a diffusion layer. The light guide layer has a great correlation with the light extraction efficiency, the diffusion layer used to control the ratio of the transmittance and reflectivity rate. We analyze the thickness of light guide layer and diffuser layer from 0.1mm to 0.4mm and 0.1mm to 0.3mm, respectively. In which the optimized package structure of thickness of light guide layer of 0.4mm, thickness of diffusion layer of 0.2mm. The prototype shows that light extraction rate of 95%, central light intensity of 25.6%, peak angle at 66° and full width at half maximum (FWHM) of 180°. This design proposed for thin, flexible, and uniform surface light source.

Freeform surfaces have drawn intensive attention in optical imaging and illumination field because of its great flexibility in optical design. However, the fabrication and testing of freeform surfaces remain a great challenge due to the arbitrary shape. Interferometry is among the high-accuracy testing method of optical surfaces. How to generate a non-rotationally symmetric wavefront similar with the surface under test and retrieve the phase from dense interferogram are hotspot issues. In this paper, we introduce two key technologies in non-null interferometry to solve the above-mentioned problems. The first is the design method of an off-axis catadioptric non-null compensator including a deformable mirror. The second is phase retrieval of single dense interferogram with digital moiré phase shifting interferogram and wavelet analysis. Simulations demonstrate the feasibility of the proposed method.

The use of aberration-theory-based approaches to optical design has been in decline ever since the development of good ray tracing software. However, as will be shown, the insights and conceptually accessible solution spaces offered by certain forms of third-order analysis of optical systems can still turn up powerful and original design concepts, that have been missed by generations of "ray-tracers". In this paper a series of surprising developments are made with respect to a wellknown optical relay. Novel solutions found by aberration-theory based approaches shall punctuate this talk, so justifying the main premise.

Freeform progressive addition lenses (PALs) are mainly divided into distance vision zone, near vision zone, astigmatism channel and peripheral astigmatism zone. The purpose of this study was to compare the effect of the width of the astigmatism channel by changing the near vision area of PALs on the basis of the minimal model method. The change of the near vision area was mainly achieved by changing the distribution function of the main curvature difference and the average curvature weight. Firstly, two weight distribution matrices of different near vision areas were designed, and the second-order partial differential equations of the minimized model were solved by the finite element method. The surface shape of two PALs was obtained. Secondly, the freeform verifier software (FFV) (ROTLEX, Israel) was used to simulate the shapes of the obtained surfaces, and used computer numerical control machine tools to process two groups of PALs. Finally, the Visionix VM-2500 lens measuring instrument was used to measure the PALs. The simulated and measured power and astigmatism distribution contours showed that the width of the astigmatism channel increased with the increase of the near vision area, however, the peripheral astigmatism was increased. Therefore, the near vision zone with an appropriate area can provide a reference for the optimal design of PALs.

Using freeform optical surface in an imaging optical system is a revolution in the field of optical design. Introducing machine learning into freeform imaging optical design will significantly reduce the human effort and even beginners in optical design will be able to perform difficult design tasks. Machine learning has been successfully applied to the immediate generation of starting points with various system specifications for the design of freeform reflective imaging systems. However, the parameters used in the network training, which are the key points in the whole design framework, are determined without proper guidance, which may significantly affect the actual performance of the networks. In this paper, a comprehensive exploration of the training parameters of the neural network used for starting points generation of freeform reflective systems is conducted. The parameters include the number of layers, the number of nodes in the layers, the type of activation function, the type of loss function, the type of optimization algorithm, and the value of learning rate. A detailed comparison and analysis of different training parameters are demonstrated on the training results and the imaging performance of validation output systems with large amount of random system specifications input. Using the obtained results designers can choose proper parameters accordingly and get desired neural networks with shorter training time and better performance. The results also offer insight in the design of imaging systems with other system configurations and more advanced system specifications.

Large aperture optical system is more and more widely used in astronomy and space optics. With the increase of aperture, the detection methods and instruments are faced with many challenges. It is difficult for traditional full-aperture detection to meet the requirements of modern large-aperture optical system. A sub-aperture inversion method for optical wavefront is proposed. Based on the relationship between the full-aperture wavefront and the sub-aperture wavefront of the optical system, the converting matrix between the sub-aperture Zernike coefficients and the full-aperture Zernike coefficients is established. The full aperture Zernike coefficients are obtained by matrix calculation. Therefore, a small number of discrete sub-aperture wavefront can be used to invert the full aperture wavefront. In this paper, the mathematical model of multi-seed aperture layout is established based on the efficiency and accuracy simultaneously, and the relevant wavefront reconstruction algorithm is discussed. In addition, the optical system detection process is simulated by mathematical simulation, and the results are compared with the results of full-aperture test, so as to verify the technical feasibility of this method. The conclusion is drawed that this method is simple and efficient, and can guarantee high accuracy even when the filling factor is low. It is an ideal method for wavefront measurement of large aperture optical systems.

The authors review three-dimensional (3D) trajectory of minute object by parallel phase-shifting digital holography. Parallel phase-shifting digital holography is a technique capable of single-shot recording of a complex amplitude distribution of object wave from a dynamic object. The authors constructed an inverted microscope based on parallel phase-shifting digital holography. The microscope consisted of a continuous-wave laser, a Mach–Zehnder interferometer, a polarization imaging camera, and a magnification optical system. A high-speed polarization imaging camera was employed to record motion picture of holograms of the dynamic specimen. Motion picture of the holograms of a minute alum crystal sinking down in the solution of alum was recorded by the microscope at the rate of 60 frames per seconds (FPS). Refocused images of the crystal were successfully obtained for all of the sinking time. The 3D trajectory of the crystal was derived from the refocused images. Also, the authors constructed an inverted and vertical microscope based on parallel phase-shifting digital holography. A Volvox swimming in a water as a living microbe was recorded by the microscope at the rate of 1000 FPS. The 3D trajectory of the microbe curvedly moving in the area of 500 μm × 500 μm × 500 μm was successfully demonstrated from the reconstructed images of the microbe.

Compact and broadband spectrometers are used for diagnosis of cancers to distinguish healthy and tumorous tissues at point-of-care locations and remote clinical centers. In this paper, we present a design of a broadband and compact spectrometer based on a three-segment grating which is able to operate from 300 nm to 1700 nm. The spectrometer has a resolution of 6 nm in the ultraviolet-visible-near infrared (UV-VIS-NIR) spectral range and 10 nm in the short wave infrared (SWIR) range. A minimum signal-to-noise ratio (SNR) of 650 in the VIS range and 9300 in the NIR- SWIR range is achieved. Afterwards, the designed three-segment grating was fabricated in-house with ultra-precision diamond tooling followed by replication in poly-methyl-methacrylate (PMMA). The replicated three-segment grating was then experimentally characterized. The experimental results show that the three-segment grating significantly improves the acquired signal level of the spectrometer in the NIR-SWIR spectral region by at least a factor of 2 compared to a corresponding single segment Richardson grating. This result opens a new way of realizing compact and broadband spectrometers which could be integrated with portable devices.

The random distribution of refractive index caused by air turbulence is an important factor affecting the accuracy of optical measurement, especially in the field of precision measurement. At present, the analysis of the influence of random refractive index medium on wave front detection in long optical system is based on practical experiments. In this paper, based on the existing ray tracing methods and image quality evaluation criteria in the medium with variable refractive index, the ray tracing is performed on the medium with long optical path with the random refractive index distribution, and the relevant influence characteristics are measured and studied. First, a set of normally distributed atmospheric density data with a constant mean value and variance are generated and the corresponding refractive index data is obtained which includes dry air density and water vapor density in the current environment. Then, the ray tracing is carried out in the random medium and uniform medium respectively. Two kinds of image quality evaluation criteria, PV and RMS, are obtained by comparing the simulation results. Through simulation, the influence of random distribution of media on optical testing results can be measured, and the post-processing of test data can be guided. The simulation results show that the larger the variance of the normal distribution of atmospheric density is, the more serious the wave front distortion is. The methods proposed in this paper can be applied to optical testing fields such as interference measurement.

The digital Moiré interferometer technique (DMIT) based on partial compensation principle is an effective approach for aspheric and freeform measurement. Besides a real interferometer, virtual interferometer, as a part of DMIT, plays an important role in the phase-shifting and alignment. The virtual interferometer based on the ray tracing, by creating a light path which is exactly the same with the actual interferometer, can obtain a simulated virtual interferogram for the phaseshifting and alignment. Generally, the ray tracing is simulated by Zemax software. However, due to the limitation of software, a communication delay between Zemax and other modules will influence the efficiency and response time of the whole system. So, how to realize ray tracing in an efficient way is still worth exploring. In this paper, we present a method for tracing ray to improve the efficiency. By using the vector formula of ray tracing, we can improve the calculation accuracy and shorten the calculation time of ray tracing, which can be used in most optical systems. Furthermore, we implement the algorithm of virtual interferometer on the basis of Visual C++, which is the software development platform of DMIT. In this way, we can integrate the virtual interferometer into the software system of DMIT, and then reduce the calling time between modules. Several simulation results are present to validate the feasibility of our method.

Refractive index is one of the most important physical parameters of the materials. Owe to its great influence on the working characteristics of an optical systems, high accuracy measurement is required. Many methods have been proposed such as the v-prism method, the minimum deviation angle method, and the interferometric method. However, for the restriction of the principle, the shape of the sample is required to be a parallel plate or a prism with a specific shape. The sample with only spherical or aspheric surfaces cannot be tested. In this paper, an improved Brewster method is proposed to measure the refractive index of optical materials with arbitrary shapes. Brewster law can be expressed as that the reflectivity of the P-polarized light approaches zero when it is incident in the Brewster angle, which is the inverse trigonometric value of the refractive index. In the original method, a parallel laser beam with P polarization is incident on the sample, and reflected by it to a photodiode to get the intensity. The minimum intensity position corresponding to Brewster angle can be found by changing the incident angle. The reflecting surface of the sample need to be planar to provide smooth reflective area with a size greater than the beam diameter. In the improved method, a laser probe focusing on the sample and an array detector are used instead of the parallel beam and the photodiode. The minimum intensity position can be found with image processing technology. Since the laser beam is focused on the sample, only a tiny area with a size of 10 microns for reflection is needed. Thus, whatever the shape of the sample is, the method can be used. In order to demonstrate the feasibility, samples with different shapes such as a prism, a parallel plate and a lens was tested, and the accuracy of the results could all reach the order of magnitude of 10^-3.

The authors present the raytracing-based method of the realistic image synthesis of the three-dimensional scenes with a complex environment containing gradient media. The proposed solution is based on the Runge-Kutta method and allows us to translate a ray to the specified distance in the free space with a gradient medium. The main specificity of the solution is the raytracing inside the medium with the complex boundary, including thousands (and sometimes millions) of geometry elements. So, an efficient way to find a ray intersection with the medium boundary becomes a serious problem. The authors designed an efficient solution for the construction of the adaptive geometry hierarchy which allows splitting the complex boundaries to the voxels with the reduced number of geometry elements and providing the fast raytracing procedure inside of the voxel. Special program interfaces to integrate the raytracing solutions to the rendering system were designed and realistic images of the scenes with gradient media were rendered. Moreover, the authors considered possible solutions for calculation of the luminance components inside of the medium with a gradient index of refraction. The investigation showed that the most efficient way of the luminance calculation is stochastic bidirectional ray tracing with a pair of photon maps. Realistic images of the scenes containing media with a gradient index of refraction were rendered.

The 5G fronthaul optical modules are the basic building block of the 5G network. With the further development of 5G, the shortage of optical fiber resources will gradually become prominent, and WDM solutions are desired. There are currently 4 WDM scheme candidates, CWDM, MWDM, LWDM and DWDM, and the debate over this issue continues. We organized the investigation and evaluation of one typical type of 25G optical modules (CWDM) from different vendors. Key parameters of optical/electrical interface have been tested and analysed, including spectrum characteristics, total mean output power, sensitivity, optical path penalty, eye diagram, power consumption as well as DDM function. Current commercial 25G CWDM optical modules are demonstrated capable to support 10 km transmission, covering almost all scenarios of 5G fronthaul.

In order to achieve a lower crosstalk, a central core-assisted photon lantern (CCAPL) supporting LP₀₁, LP₁₁, LP₂₁, LP₃₁ and LP₀₂ modes is proposed, whose performance is evaluated through numerical simulation based on BPM as well as FEM. Compared with the depressed-index central core PL, it can be found that the average mode loss are reduced by about 0.05 dB and 0.1 dB, while the corresponding worst mode crosstalk is reduced by 3.3 dB and 6.5 dB for the step-index (SI) and grade-index (GI) profile, respectively. For comparable performance, the length of the CCAPL can be about 3-cm shorter than that in the depressed-index central core case, which is easier to process and avoids secondary taper in some cases. With optimized structural parameters, the losses of LP₀₁, LP₁₁, LP₂₁, LP₃₁ and LP₀₂ modes in the SI device achieve -0.09 dB, -0.05 dB, -0.04 dB, -0.04 dB, and -0.06 dB, respectively. On the other hand, the mode losses in the GI device come to -0.03 dB,-0.04 dB, -0.04 dB, -0.02 dB, and -0.12 dB respectively. Besides, the modes’ crosstalk of the SI type and GI type are below -22.3 dB and -21.0 dB for all modes, respectively. As a conclusion, the impact of the assisted core on GI devices is greater than that on the SI devices.

The 360 ° panoramic system is a critical component of modern vehicle safety system. However, the existing fisheye lens design generates a large amount of barrel distortion, i.e. low resolution of the edge scene. Moreover, for night driving scenarios (the operating mode in the infrared band), the current conventional systems are lack of good performance capabilities. To solve these problems, in this work, we proposed a novel car panoramic system. We analyzed the general characteristics and implementation methods of the existing panoramic imaging system. The design of the novel car panoramic system is given. We also analyzed the tolerance of the whole system and designed its mechanical structure and coating. The MTF value of the proposed car panoramic system is higher than 42% in 90lp/mm for visible part and 50% in 20lp/mm for infrared part.

We demonstrate a simple design method to be applied in designing of LED collimating systems. In the first stage, we have considered several zones in a lighting beam and analyze their aberration properties, in the second stage we combine zones into a whole system taking into account the possible residual divergence of the beam. Compared to the analogous design methods, the method gives a possibility to choose the size of zones more consciously and evaluate the divergence without complicated and huge computations. Additionally, the derived equations give us an opportunity of understanding possible collimating properties of a system before the design. An example is given of a highly efficient collimating lens working with a 1 mm ×1 mm Lambertian LED. According to the simulation result, the optical efficiency of about 90% of light flux inside the angle of ±5 deg is achieved.

Reflective system of four mirrors has a small volume and good image quality, which is used popularly in space detection and airborne filed. Here the formula of reflective system with four mirrors is deducted based on the third-order aberration，secondly the initial configuration of reflective system is calculated with formula, then the data of initial configuration is optimized by optical software ZEMAX. The off-axis reflective system is obtained based on the coaxial reflective system, the freeform surface is also added to extend the view field, finally an off-axis reflective system with large view field is designed and obtained.

The development of devices based on an acousto-optical filter (AOTF) is widespread. It is essential to be able to accurately simulate acousto-optic diffraction when modelling optical systems that include AOTF. However, the AOTF model is not a built-in object in optical design software. From the other hand, it is usually impossible to integrate the properties of AOTFs calculated in other special software into a standard optical design program. Therefore, in this paper, we considered possible methods for evaluating and modelling the characteristics of AOTFs in the design of optical systems.

To measure different parameters of a spherical lens simultaneously, a method by low-coherence interferometry with a low temporal coherent light source is proposed. This proposed method can obtain both the radius of curvature and the central thickness of a spherical lens in a single optical system. Owing to the property of low temporal coherence, the contrast of interference fringe pattern, hologram, varies with the optical path difference of an object beam and a reference beam. This enables the central thickness of the test lens to acquire with a Michelson interferometer. Simultaneously, the spherical shape of the test lens, namely the radius of curvature, can be obtained from a hologram which contains information of the wavefront curvature from the reflected beam of the spherical surface of the test lens.

The damped least squares (DLS) method is widely used in optical system design due to its great advantages in the speed of convergence and robustness. However, it is easy to get stuck into local minima, which is probably very close to the starting point, leading to a small search range. The particle swarm optimization (PSO) algorithm is one of the most popular intelligent optimization algorithms which is used to handle problems with a large number of variables benefits from its great randomness. It is helpful to use PSO to deal with situations when getting stuck into local minima. It can jump out of the local minima easily for its randomly searching mode. In this paper, we proposed a novel optimization method for the optical system design which is based on the combination of the improved PSO with DLS to achieve a balance between local and global optimization. By combining the improved PSO with DLS, we can prevent the whole system from falling into the local minima and improve the stability of the algorithm. First, we use the improved PSO to search in the planning area randomly. Second, after finishing the process of SA-PSO, the DLS is added to continue optimizing in a small range to find the final solutions. A machine vision lens has been designed by our proposed optimization algorithm, and the results demonstrates that this algorithm is effective for optical system design.

A vortex half-wave retarder (VHR) is a new type of polarizing element with a constant retardance across its clear aperture but its fast axis rotating continuously over the area of the optic. In polarization optics, the VHR-based polarization control method is very efficient to control the radial and azimuthal polarization states of light with a simple system configuration, ease of use, and high energy utilization efficiency. In optical manipulation, VHR can generate nondiffracting Bessel beams with an enlarged trapping region of optical tweezers. In the field of optical imaging, an imaging system with a vortex half-wave retarder has been reported to improve the resolution. Due to its many unique functions with novelty, vortex half-wave retarder has received a lot of interests in optical micro-operation, optical imaging, optical communication, optoelectronics, quantum information and remote sensing. In this paper, we study the performance evaluation for imaging with a 0-order vortex half-wave retarder by using a method referred to as Optical Transfer Matrix. After introduction of the Jones matrix for the vortex half-wave retarders as a general pupil matrix, we present the optical transfer matrix as the frequency transfer characteristics for the imaging system. As compared with a polarization imaging with a half-wave plate, the imaging system with a vortex half-wave retarder has a typical effect of apodizing by increasing a contrast for the high-frequency end.

There is a strong demand for beam steering aiming to reposition an optical beam in various fields of applications, such as optical communications, light detection and ranging, microscopies, displays. In this paper, we present a beam steering method actuated by a hydraulic polymer elastic membrane. A thick polydimethylsiloxane (PDMS) membrane is placed underneath a thin PDMS membrane. The beam steering angle can be varied adaptively through inputting different hydraulic pressure. The thin PDMS membrane deforms significantly and the thick PDMS membrane deforms slightly since there is enough thickness difference between thick and thin PDMS membrane when the liquid pressure is applied. The model of the adaptive beam steering method is built and some simulation experiments are carried out by COMSOL Multiphysics software. The effects of some model parameters are analyzed. The parameters include the thickness ratio, the distance between the thick PDMS membrane and the acrylic frame, the length of the thick PDMS membrane, and liquid pressure are studied. We can find that the linearity of the effective refractive surface increases with the increase of thickness ratio and decreases when the thick PDMS membrane is close to the acrylic frame. The beam steering angle increases with increasing of the liquid pressure. We also find that there is a tradeoff between the length of the thick PDMS membrane and the range of the beam steering angle. The results show that the appropriate thickness ratio of the thick and thin PDMS membrane is 7:1. The beam steering angle is 0°~33.46° when the liquid pressure is 0 kPa~8 kPa. The length of the thick PDMS membrane is 7.5 mm. This paper can be used to design an adaptive beam steering device actuated by the hydraulic pressure.

A full-parameter simulating software is developed for closed loop fiber optic gyroscopes (FOGs), which is a very powerful tool for designing and optimizing a FOG. It is visual for researchers to investigate the photoelectric signal processing at all stages in FOGs. All optical and electrical components in FOG, including light source, coupler, MIOC, PMF coil, photodetector ADC, DAC and digital circuit, are modeled numerically in the software. The analyses of the amplitude effect on the spectrum of the light source, the modulation and feedback signal and the half-wave voltage adjustment using the software verify the power of the software.

Silicon photonics has emerged as an attractive technology for developing low-cost and high-speed optical communication and optical interconnects. We design a test station which enables semi-automatic for optical-optical and electro-optical testing of passive and active device. Advances in automated wafer-level optical test enable statistical photonic device characterization for development, photonic modeling, and manufacturing controls. Meanwhile we study the influence of fiber tilt angle and height on the measurement.

The statistical properties of the scattered light from a moving random birefringence screen is investigated in terms of the mutual coherence matrix for the electric field. The relationship between the statistical characteristics of the scattered light from the scattering surface and the microstructure of the anisotropic medium is explored to understand the potential mechanism of the surface scattering phenomenon of electric fields with random polarization states and the proposed method provides a convenient means to realize the depolarization and decoherence.

It is a hybrid design spectrometer with MWIR zooming and spectral imaging. The system realizes the searching in large field of view and recognition in small field of view which can resolve the difficulty that the target and background of spectrometer are not easy to distinguish in a single field of view. It also decreases the difficulty of spectral analysis and data dimension reduction. The collimating light beam modulated by AOTF (acousto-optic tunable filter) provides a basis for the subsequent spectral analysis. The optical system realizes three times zoom from 160mm to 480mm. The simulation achieves the effect imaging result. Experiments show that the system has both imaging and spectral recognition capabilities.

As a new type of laser gain medium, sesquioxide crystal has significant advantages in thermal conductivity, phonon energy and other properties. It has an important application in improving the performance of picosecond/femtosecond laser. However, due to its hard and brittle characteristics, the machining process is prone to pitting, cracks, microcracks, sub surface defects and other damages, which brings great difficulties and challenges to its polishing process. In order to solve the above problems, a new chemical mechanical polishing slurry is proposed, which includes alumina, cerium oxide, aluminum sulfate, urea and pure water. After polishing with this slurry, the surface roughness of the crystal is better than 0.4nm, the damage depth of the sub surface is better than 1.5 μm, the surface shape is close to 1/10λ, and the material removal rate is up to 48nm / min. Based on the analysis of the results of small angle grazing X-ray diffraction and X-ray photoelectron spectroscopy (XPS), this paper describes the production of ReOHCO₃ by the reaction of urea and Re₂O₃ in the new polishing slurry. The hydration layer composed of ScOOH and Sc2(SO₄)₃ is formed on the surface of alumina/ aluminum sulfate and crystal, and the soft product is removed by ceria to form a smooth and low damage crystal surface.

Recently, the phones with high screen-to-body ratio are popular in the market, and it leads to the demand of in-display fingerprint recognition. The optical fingerprint sensor is based on frustrated total internal reflection (FTIR), and the camera type independent on the panel process is cost-effective and with high yield rate. To meet the volume constraint of the smart phone, a miniaturized compact lens is designed. For maximizing the sensing area in the limited space, the field of view can reach 128°. To increase the accuracy and speed of the recognition, the design has extremely small distortion and low f-number. Mostly importantly, the resolution should be sufficient for the fingerprint extraction algorithm. To achieve the specifications, the lens is designed with three aspheric plastic lenses using injection molding. In this paper, the procedure of optical design, mechanical design, lens fabrication and assembly of the prototype is presented. Finally, the prototype is employed for fingerprint identification.

Multiple configurations system and its influence and control on aberration are the basis for the design of such systems and have practical value in engineering. The principle, modeling and error analysis are analyzed. Based on the system configuration of the compound zoom system, moreover, this paper advances the algorithm analysis. With an interval which between the elements as the initial amount, the form of motion of the elements is used as the free amount, and the distribution of the optical focal length and the form of the element motion can be obtained by calculating the equation sets. Compared with the traditional method, the global synthesis can significantly improve the design in effect and efficiency.

We propose a scheme of ultraviolet (UV) communication system with low-density parity-check (LDPC) code. LU decomposition algorithm is adopted as the channel coding algorithm and log likelihood ratio sum-product algorithm (LLRSPA) is adopted as the channel decoding method. In this paper, additive white gaussian noise (AWGN) model is used to simulate the influence of noise on the ultraviolet signal in the atmospheric channel and cut-complementary (CC) model is used to forecast the path loss of UV communication system. The bit error rate (BER) performance of UV communication system is studied by simulation from aspects of transmission power, photoelectric conversion efficiency, filter transmittance, transmitter and receiver elevation angle. The simulation results show that, in a non-line-of-sight (NLOS) case, the communication distance can achieve about 200m with 10⁻³ BER when the transmission power is 260mW.

The risk of the occurrence and spread of various biological threats dictates increased requirements for the accuracy and speed of their detection. So, the work is devoted to design of the microlens with high image quality without digital processing at different environment’s temperatures. Thus, it allows investigating biological tissues in collecting place and reducing the time of diagnosis.

Knowledge of the structure of vitreous floaters is crucial to evaluate the need for surgical removal of these floaters. We simulated the phase retrieval of microstructures simulating vitreous floaters by an algorithm PhaseLift and investigate the effects of various parameters on the retrieved phase. The object under test was modulated and the coded diffraction patterns were calculated. Next, PhaseLift was used to retrieve the phase. In the current study, we simulate the effect of Gaussian and Poison noise on the phase retrieval of pure phase objects. We apply an iterative algorithm PhaseLift for phase retrieval as this algorithm requires a very few modulating masks and is able to retrieve the phase of an object from very sparse data. Both types of noise are added to the intensity measurements and their effect on the retrieved phase is assessed in terms of the root-mean-square error. We conclude that Poisson noise compromises the accuracy of phase retrieval more compared to Gaussian noise given that the levels of both types of noise are equal. We also conclude that the thermal noise having nearly Gaussian distribution is of less importance compared to the shot noise having Poisson distribution and dominating at low-light levels.

Continuous phase plate (CPP) is an important diffractive optical element, which is widely used in high power laser devices. The continuous phase plate with a small aperture period of 4 mm is processed by the atmospheric pressure plasma polishing (APPP). Through the study of the reaction mechanism, it is found that the removal volume has a non-linear relationship with the dwell time, which will lead to machining errors. Based on this, a dwell time compensation method is proposed, and the machining program is generated according to this relationship. A 70mm × 70mm × 20mm continuous phase plate was fabricated by using the processing program generated by this method. The processing time was 4.5h, and the surface residual converged to 57.188nm RMS. The experimental results show that the method can effectively calculate the removal function under different dwell time, and significantly improve the machining accuracy.

Continuous phase plate (CPP) has been widely used in high energy laser optical systems such as inertial confinement fusion (ICF) due to its high energy efficiency and easy control of focal spot shape. At present, Magnetorheological Finishing (MRF) technology is one of the main means to realize CPP high precision processing. This paper analyzes and optimizes the error factors that affect the accuracy improvement in CPP machining process, such as tool path, removal function characteristics, positioning accuracy and material removal amount. The main error source surface shape matching error is analyzed and the frequency domain cross-correlation matching algorithm based on Fourier transform is used to realize the sub-pixel level height between the actual wavefront and the theoretical design wavefront accurate registration. Based on the results of process optimization, the high-precision processing of CPP with the design feature size of 10 mm, the peak to valley (PV) of 1 λ (λ = 1053nm) and gradient rms of 0.82 λ/cm was processed with MRF technology. Through the iteration of two processing stages, the matching accuracy between the processing wavefront and the theoretical wavefront is controlled at 10.5nm (root mean square, RMS), which lays the foundation for CCP processing with larger diameter and smaller cycle.

Different light-fields information collection methods will cause different light-fields information cannot be fused and recorded into the holographic stereogram. In order to print the holographic stereogram recording information of virtualreal fusion, the depth-image-based rendering (DIBR) technology is applied to the holographic stereogram fabricated by effective perspective images’ segmentation and mosaicking method (EPISM). This method firstly obtains matching real scene sampling parameters according to the virtual scene, and combines with the improved DIBR technology to draw the initial perspective images without holes or crack problems. After EPISM processing, the synthetic perspective images of real and virtual scenes with the same parameters are fused. Finally, the fused perspective images are recorded into holographic stereogram. The experimental results demonstrate this proposed method obtain high quality virtual-real fusion display.

Modern optical imaging systems should have high image quality in a wide spectral range from UV to IR; therefore chromatic aberrations are corrected minimum for three wavelength of waveband. Method for prediction of chromatic aberration in the spectral range of interest by known value of chromatic aberration in the other waveband is presented.

The article presents an effective and physically correct method of the stochastic ray tracing through hologram optical elements. The method provides photorealistic rendering of 3D scene images formed by optical systems containing HOE. It also accounts the diffraction scattering on hologram elements. We realized this approach for virtual prototyping of the augmented reality optical system with two HOEs, projecting an image from an LCD matrix through a light guide system into the eye of an observer. Particular attention is paid to stochastic ray tracing methods for holograms recorded with an extended reference source that simulates the scattering of light by scene objects.

The study addresses the problem of designing an optical system with freeform surface elements. It proposes the modification of the Light Energy Mapping Design Method for the task of designing an optical element for low-intensity obstruction light. Also, there is an algorithm for calculating optical elements described for such devices. The results of calculating and virtual prototyping of devices designed by the proposed method.

Real-time quantitative PCR technology has been an active filed since it has excellent performance of the ability of quantitative analysis for initial DNA template evaluation and detection on fluorescence signal. This paper basically pay attention on the features of system and optimize the original parts of the device. Using OLED as light source and nonlinear optics device in the light path to optimize the effect of the device. According to simulation results, the uniformity of the excitation in this device has a marked improvement. Furthermore, with the addition of the filed lens, the collection effect of the fluorescence would be better.

The compound eye optical system has attracted much recent attention, owing to its large field-of-view, compact structure, and rapid imaging capabilities. We designed a compact image scanner (cross-section 36.5 mm × 17 mm) based on the compound eye system. A single imaging unit is mainly composed of two freeform mirrors and a flat mirror, and its field-of-view in object space reaches 10 mm. The modulation transfer function of the system is greater than 0.6 at 12 cycles/mm corresponding to Nyquist spatial frequency of 600 dots per inch in depth-of-field of 0~4 mm. Furthermore, a larger field-of-view is achieved by splicing multiple imaging units with 1-mm overlap in object space. An object-side telecentric system is used to obtain constant magnification at different object distances and the distortion (<1 μm) is controlled by freeform mirrors. The final image is obtained by image splicing. The imaging quality of the scanner is further improved by eliminating stray light.

As a computational imaging method, phase retrieval has wide applications in image reconstruction, wavefront detection, image encryption, etc. It is an image-based wavefront sensing technique and compared with some other traditional measurement methods such as interferometry, phase retrieval has the advantages of easy operation, high accuracy and strong adaptability to the environment. Conventional phase retrieval algorithms, such as the Gerchberg–Saxton (GS) algorithm, retrieve wavefront by iterative calculation. But limited by finite information of the captured diffractive light filed, the calculation process is easy to fall into local minimum value and stagnation occurs in practical, making it unable to converge to the right wavefront. In this paper, in order to improve this phenomenon, a phase retrieval method combined with the zone plate is proposed in this paper. In this method, zone plates are added into the traditional iterative phase retrieval algorithm to modulate the incident wavefront and combined with the multi-focus property, it can collect more effective information about the wavefront in a single optical intensity distribution image and realize a better wavefront reconstruction result. Simulation results indicate that by taking zone plates into calculation, more effective reconstruction results can be acquired. On the one hand, the recovery residual is smaller compared with conventional lens. On the other, although all of these methods reach to a stagnation, zone-plate-based methods are more efficient to get a better result.

Spectacle lens are used to compensate refractive errors of the eyes. Therefore, the properties of human eyes were taken into consideration in our research. We not only designed and optimized the lens with the required optical performance in ZEMAX based on the eye-lens system, but also calculated the sag of the aspherical surface according to the optimized parameters. The back surface of the lens was aspherical surface for the better clinical effects than other types of aspherical lens. The results data were subsequently imported into the freeform verifier software (FFV) for analysis and the optical properties of the lens were calculated. It was found that the power distribution has been improved. The thickness of aspherical lens was much thinner than the spherical lens. Therefore, our research found a balance between thickness and optical performance.

The design of a highly reflective interference coating with the ability to control the laser induced damage threshold is calculated. The coating consists of twenty-five quarter-wave layers formed of silicon nitride and silicon dioxide with a sublayer of silver on an optical element made of quartz glass grade KU-1. One of the layers which was formed from silicon nitride has a half-wave thickness to obtain a structure like a Fabry-Perot interferometer. A relationship is established between the structure of the interference coating and the magnitude of the electric field strength in the layers when exposed to laser radiation. The introduction of a sublayer made of silver deposed on a substrate into the construction of a dielectric multilayer coating allows one to obtain a reflection coefficient at a control wavelength of greater than 99%. In this case, the fraction of laser radiation incident on the silver sublayer is less than 0.5%.

The industrial sector for intraocular lenses (IOLs) is constantly searching for new lens models to improve vision quality of patients after cataract surgery. This paper presents a biconvex intraocular lens with a bidimensional refractive sinusoidal profile distributed over its posterior surface. This type of pattern allows the configuration of different amplitudes and frequencies of the orthogonal sinusoidal functions, leading to different optical performance. The choice of parameters enables the IOL to behave as Monofocal, Multifocal or Extended Depth of Focus. The intraocular lens under test is modelled and inserted into a modified Liou-Brennan eye model. The parameters are systematically varied and a custom methodology is employed to verify into which class a lens described by a certain set of parameters falls. After the classification algorithm, some IOLs are selected to have their performance evaluated through an image analysis that consists of different visual acuities for an object at a given distance from the eye. Also, an estimated preclinical defocus curve is simulated for those selected IOLs. This methodology can be used as a reliable tool to assist lens manufacturers in industry to evaluate optimal design parameters.

Automobile lighting system is an important guarantee for the safe driving of cars at night. In view of the complex structure of the current LED headlamp system and weak penetrating ability, a laser-filled LED far and near beam integrated automotive headlamp optical system is designed. Theoretical calculations show that the low beam light passes through the low beam cone set. The light device is totally reflected, and the outgoing light is condensed to the focal point of the baffle. The focal point of the baffle coincides with the upper focal point of the special-shaped lens, and the required low beam is obtained by the upper part of the special-shaped lens reflected. Whether the center of the highbeam cone condenser coincides with the lower focus of the special-shaped lens to obtain the required high-beam. The laser light source is emitted through the small hole in the lower part of the special-shaped lens, and the center of the laser spot and the center of the high beam spot are overlapped by the deflection angle. The high beam fill light effect verifies the rationality of the optical system. The simulation results show that the designed optical system of the automobile headlamp complies with the national standards. The headlamp optical system has a reduced volume and strong penetrating ability, which is in line with the current development direction of laser car lights and smart car lights.

This research considers the influence of the structure of an interference reflective filter, structure of which includes interference layers made of non-absorbing dielectric materials, on the stability of its spectral characteristics with a change in the angle of incidence. A reflective filter is formed from the layers of equal or multiple optical thickness made of two film-forming materials. Our research has shown that with reducing difference between refractive indices of the filmforming materials, the bandwidth of stop-band decreases. The FWHM of stop-band of the filter is determined by the refractive indices of the film-forming materials. The dependence of stop-band shift on the wavelength scale with a change in the angle of incidence on the multilayers of dielectric structure has been established. The obtained function allows to impose restrictions on the film-forming materials to ensure a minimum shift of the spectral characteristic in a wide range of the angle of incidence.