ZEMAX Software Research Articles

Simplified Aberration Analysis Method of Holographic Waveguide Combiner

Generally, the diffractive waveguide combiner and computer-generated hologram (CGH) technique have the potential to achieve compact head-mounted display (HMD) with a natural 3D display function. However, the diffractive waveguide combiner will degrade the image quality because of aberration. In order to resolve this issue, the complex analysis based on the ray-tracing method is necessary. Since the major aberration of the waveguide combiners is only astigmatism and anamorphic distortion, only these two aberrations were discussed in this paper. Furthermore, two common waveguide structures were discussed here. In total, four formulas were summarized to analyze aberration and anamorphic distortion in these two structures. Finally, the simplified formulas were verified with the commercial ray-tracing software Zemax. The calculated results of the proposed method match the simulation of Zemax software well. Therefore, the aberration of an arbitrary similar diffractive waveguide can be analyzed by the proposed method. This will make the designing process simpler and faster.

Calculation of the wave aberration of field curvature and color aberrations of an ultrawide-angle optical system

Based on the aberration theory of plane-symmetric optical system, this paper develops a method for calculating the wave aberration of the field curvature and color aberrations of each optical surface in an ultrawide-angle optical system, which enables us to analyze, like Seidel aberration theory, the contribution and balance of these aberrations between different optical surfaces. We then apply the resultant formulas to calculate the wave aberrations of the field curvature and color aberrations of two optical lenses, and compare the results with the corresponding wave aberrations values obtained from Seidel aberration theory and Zemax software. The study shows that accuracy of the results obtained with our formulas are quite satisfactory even in the large range of field view while the accuracy of those with the Seidel aberrations is limited by the field angle. Our method can provide an effective means for aberration analysis and optimization design of an ultrawide-angle optical systems.

Mueller matrix of imaging polarimeter's optical system-comparison of simulation results obtained using Zemax and MATLAB software with experimental data.

A procedure for simulating the Mueller matrix of an optical system across the field of view of a long-wavelength infrared (LWIR) imaging polarimeter is presented in this paper. The procedure is based on a ray-tracing model and uses off-the-shelf software and custom add-on procedures written in MATLAB. A simulation was conducted to obtain polarization ray tracing across the entire surface of the focal-plane array for a set of wavelengths within the LWIR (8-14 µm) window and within the instrument's field of view of 7.3∘×5.5∘ with a set of different starting polarization states. Finally, the simulation results are compared with measurement data obtained from the home-designed optical train of a polarimetric camera. For Mueller matrix entries significantly larger than zero, both simulation and experiment results show high consistency, with overall RMS error of less than 2%. The presented results are useful when anticipation of a Mueller matrix of an imaging polarimeter is of high importance.

Modeling of an X-ray grating-based imaging interferometer using ray tracing.

X-ray imaging by means of a grating-based Talbot-Lau interferometer has become an important tool for a wide variety of application areas such as security, medical and materials analysis. Imaging modalities include attenuation, differential phase contrast, and visibility contrast (or so-called dark field). We have developed a novel modeling approach based on ray tracing with commercially available software (Zemax OpticStudio) that yields image projections for all three modalities. The results compare favorably with experimental findings. Our polychromatic ray-based model accommodates realistic 3-D CAD objects with tailored materials properties and also allows for both surface and bulk scattering. As such, the model can simulate imaging of complicated objects as well as assist in a physical understanding of experimental projection details.

Compact and contactless reflectance confocal microscope for neurosurgery.

Visual guidance at the cellular level during neurosurgical procedures is essential for complete tumour resection. We present a compact reflectance confocal microscope with a 20 mm working distance that provided <1.2 µm spatial resolution over a 600 µm × 600 µm field of view in the near-infrared region. A physical footprint of 200 mm × 550 mm was achieved using only standard off-the-shelf components. Theoretical performance of the optical design was first evaluated via commercial Zemax software. Then three specimens from rodents: fixed brain, frozen calvaria and live hippocampal slices, were used to experimentally assess system capability and robustness. Results show great potential for the proposed system to be translated into use as a next generation label-free and contactless neurosurgical microscope.

Compact Imaging Systems Based on Annular Harmonic Lenses.

In this study, a configuration of a compact imaging objective based on a reflecting annular harmonic lens was proposed. Light propagation through the proposed optical system was comprehensively modeled using a dedicated special program and the ZEMAX software, with the latter used to derive the point spread function (PSF). Several relationships were used to describe the connection between key parameters of the objective, including its focal length, field of view, and thickness. We demonstrated that it was possible to design a compact imaging objective whose overall length could be one to two orders of magnitude smaller than its focal length. Using direct laser writing, a reflecting annular harmonic lens was fabricated and used in the proposed objective scheme. The performance of the objective was experimentally studied by imaging a light source and a test pattern. The performance of the compact imaging objective based on a reflecting annular harmonic lens was verified in principle. A PSF value of approximately 16 microns was experimentally obtained, for a lens with a diameter of 25 mm with a focal length of 100 mm.

FOUCAULT KNIFE-EDGE METHOD APPLICATION FOR ADAPTATION OF THE MILLIMETRON OBSERVATORY MIRROR SYSTEM

In the process of space telescopes development there is an increase in the diameter of their reflector.In this case, composite reflectors are used more often. So the main mirror of the Millimetron observatory consists of 96 elements, each of which can deviate from the calculated position during the transition to the transport position and back to the working position when the telescope is put into orbit. In this paper, we consider the possibility of using Foucault knife-edgemethod to solve the problem of adapting the mirror system of the Millimetron observatory. An optical scheme for solving the adaptation problem is proposed. It was simulated in the Zemax software package. In the process of modeling, the effects arising from the deviation of all the components of the reflector in 6 degrees of freedom were studied. The advantage in the approach to the digital matrix in the telescope is highlighted.

Optical design of a crossed double-grating spectrometer for extracting pure rotational Raman lines of N2

In this paper, we introduce a spectrometer design with crossed double-grating for extracting pure rotational Raman (PRR) lines of N2. The design applies a linear optical fibre array as the entrance slit and a linear array photomultiplier tube (LaPMT) as the detector. The linear dispersion and structural parameters of the proposed configuration were analysed theoretically, and the optical layout of the spectrometer was simulated using the Zemax software. A spectrometer with a 32-channel LaPMT was simulated to obtain the PRR spectrum of N2 when the excitation wavelength was 532 nm. The Stokes and anti-Stokes Raman lines, with rotational quantum states from 0 (2) through 14 (16), were obtained on separate channels of the LaPMT, and the resolution was approximately 0.22 nm per channel.

Design of a Multi-sensor Monitoring System for Additive Manufacturing Process

Additive manufacturing (AM) technology is becoming increasingly feasible in industrial applications. Although AM systems continue to improve, the lack of repeatability and stability of these technologies remains an obstacle to industrial breakthroughs. Thus, AM process monitoring equipment has to be set up to supervise product quality and detect defects. This study first reviews the various categories of defects, relevant AM process signatures, and optical monitoring methods of powder bed fusion processes proposed so far. Then, according to the detection requirements, an optical process monitoring system based on multiple sensors is proposed, which is equipped with a white light imaging channel, an infrared imaging channel, and a polarization imaging channel. The aberrations can be optimized using Zemax software by appropriately selecting the optimization function operands. Thus, the design requirements for the multi-sensor monitoring system for the AM process can be achieved.

Time-dependent 3D modeling of the thermal analysis of the high-power diode laser hardening process

In this paper, the thermal analysis of the high-power diode laser hardening process was modeled on AISI 4130 steel. Afterward, the depth and width of hardness were predicted based on the complete austenite temperature (AC3). Due to the dimensions and output beam power of the diode laser stack (DLS), it is impossible to achieve the suitable power density (103-105 W/cm2). Furthermore, the output intensity profile of the DLS is not homogeneous because of the pitch between the emitters. Thus, to achieve a suitable power density and a uniform beam profile, an optical layout was designed. The beam profile was experimentally obtained by a beam profiler at different distances from the focal plane and was compared with the modeling results. Due to the agreement between the modeling and experimental results, the intensity value of each mesh of the laser profile was extracted from the ZEMAX software. Then, for the thermal analysis of the laser hardening process (LHP), it was entered as a heat flux input into the COMSOL Multiphysics software.

Design of spherical aberration free liquid-filled cylindrical zoom lenses over a wide focal length range based on ZEMAX.

A systematic design idea for liquid-filled cylindrical zoom lenses with ideal imaging quality over a wide focal length range is introduced in detail. The PWC method is used to calculate the initial structure parameters of the zoom lenses, and the optical design software ZEMAX is used to eliminate the spherical aberration at different focal lengths. Lenses named SLCL-Doublet are finally designed, which are formed by a symmetric liquid-core cylindrical lens (SLCL) filled with variable refractive index (RI) liquid and a doublet cylindrical lens capable of significantly weakening the spherical aberration. The focal length of the SLCL-Doublet continuously decreases from 101.406 mm to 54.162 mm as the liquid RI changes from 1.3300 to 1.5000. Calculated over 75% of the full aperture, the root mean square (RMS) spot radius of the SLCL-Doublet is always less than 7 µm over the whole focal length range, and the peak-to-valley wavefront error remains below the λ/4 limit when the focal length ranges from 62.373 mm to 65.814 mm, within which the lenses approach the diffraction limit, demonstrating improvement in the optical performance over that of previously designed liquid-core cylindrical lenses. The sources of potential fabrication and installation errors in the practical implementation of the SLCL-Doublet are also analyzed in detail. The SLCL-Doublet is demonstrated to be characterized by high imaging quality and easy installation, which enriches the types of core optical element for measuring the liquid RI and liquid diffusion coefficient and provides guarantee for improving the measurement accuracy.

Light transmitting performance and energy-saving of plastic optical fibre transparent concrete products

Buildings consume large amounts of energy, and lighting consumes a substantial amount of this energy. Therefore, an alternative technology that depends more on natural lighting is needed in order to reduce the building energy consumption. In this paper, based on the excellent properties of light guiding and elasto-optic effect of optical fibre, a novel transparent concrete with plastic optical fibres (POFs) arranged into the concrete was developed and evaluated. The light transmitting performance of plastic optical fibre transparent concrete product (PTCP) was tested by optical power method. The ZEMAX software was used to simulate the transparent test, and the prediction model was established to predict the light transmittance of PTCP. The evaluation of the energy-saving effect due to the use of this building material was studied using the Autodesk Ecotect software. The results showed that PTCP possesses excellent light transmittance property, which was proportional to the content of the optical fibres. The model established by ZEMAX can effectively predict the transmittance of PTCP. The average daylighting factor of the room built with PTCP was increased by nearly 30%, the lighting uniformity was upgraded by nearly 40% and nearly 20% reduction in energy consumption was realised.

Zemax ray tracing model for plasma waveguides

Plasma-based waveguides are currently employed for laser wakefield acceleration to extend the focal region of laser beams. A parabolic transverse plasma density profile, suitable for laser guiding, can be established in a dielectric capillary as a consequence of a discharge in gas. In this work, we report on a new ray tracing model, based on the Zemax software, able to simulate the envelope of a laser beam propagating through a plasma waveguide. The potentialities offered by Zemax in terms of geometries and materials and the possibility to create custom objects do allow the simulation of complex and various scenarios, as for example curved plasma waveguides.

Optical Machine Remote Sensing Platform and Its Thermal Field Simulation Analysis

The article introduces a three-axis aerial remote sensing imaging platform that can flexibly and accurately acquire ground target images in the air. Then it analyzes the impact of various complex conditions on the imaging quality, and finds that temperature change is the key factor affecting the imaging quality of the aerial remote sensing platform. The thermal field analysis of the designed optical lens part of the aerial camera was carried out. The thermal field analysis of the lens model in the finite element analysis software was used to extract the displacement vector of each node of the lens under different temperature fields. The mirror data is fitted using the Zernike polynomial program written in the matlab software. And the Zernike polynomial program brings the coefficients of the obtained zernike polynomial into the optical design software zemax for image quality evaluation, and completes the thermal field analysis of the optical system. Do the foundation for further research.

Design of large field of view curved optical system based on ZEMAX

Structural design solved the problem in the paper that the large field of view and high resolution of the compound eye optical system can not be realized simultaneously. A curved compound eye system including a 3-ring lens group is designed. The compound eye system is divided into two parts: the central sub-eye system and the edge sub-eye system. The edge sub-eye system reduced the complexity of processing because of the same lens group. In the design process, we systematically studied the field of view between the single sub-eye system and the compound eye system, and obtained the arrangement of the sub-eyes. Then, the geometrical model of a single sub-eye system stitching is presented which is based on the conjugate relations between the incident and exit window. The whole field of the compound eye system designed by this method could reach up 79.5°, the angular resolution of the center system is 0.01°, and the angular resolution of the edge system is 0.017°. Compared with traditional single aperture optical system, the image quality of edge field of view is greatly improved, and the ability to acquire the target orientation is improved. Finally, the correctness of the optical system is validated with the optical design software ZEMAX. And this research could further promote the application of compound eye imaging system.

Optical design of a new folding scanning system in MEMS-based lidar

In order to solve the two disadvantages, serious divergence and limited scanning angle, of the traditional optical angle expansion in MEMS-based scanning system, a new method is proposed, i.e. an f-theta lens group and a wide-angle lens group are added into the traditional one. Principle of the optical angle expansion is discussed, while the relationship between emergent angle and incident angles has been given. Employing the optical design software ZEMAX, a folding scanning optical system based on MEMS mirror is designed thereafter. The folding scanning optical system we designed can not only scan in a large angle field, which is greater than 60°, but also obtain small spot size at distance of about 160 m, where the spot size is less than 10 cm. This folding scanning optical system has a significant application value in 3D imaging lidar system.

Analysis and optimization of the Glass pattern realized by a microlens array.

It is well known that the superposition of two identical random dot patterns may give rise to a particular form of moiré effect known as a Glass pattern. By integrating a microlens array and a micropattern array and applying a small geometrical transformation, it is possible to show the parallactic or the orthoparallactic motion effect when varying the viewing angle. In this paper, we study the effect of the structural parameters of a Glass pattern optical system on its image quality. The position of each elemental pattern in the micropattern array is derived based on a revised model that considers the finite observation distance. The image quality is evaluated by the ray analysis on the observation plane and the reconstructed image plane. Rays from different pixels of the micropattern array are evaluated by the spot size. The depth of the Glass pattern in image space is also analyzed. In addition, a Glass pattern optical system is simulated and optimized by ZEMAX software. An optimal result is obtained that validates the theoretical analysis. Our study can find potential application for designing Glass pattern optical systems or optimization of those imaging systems based on microlens arrays.

Dispersive Optical Systems for Highly-Concentrated Solar Spectrum Splitting: Concept, Design, and Performance Analyses

We present a concept design of a solar spectrum splitting system that enables highly-concentrated solar energy harvesting over the entire AM1.5 spectral range. After passing through an array of the dispersive optical system (DOS) module composed of a grating structure and dispersive prisms below a concentrating lens, incident sunlight can be separated into two wavelength bands of visible (VIS) and infrared (IR) ranges, which can then be focused onto corresponding solar receivers. Based on the spectral response of typical crystalline silicon solar cells, the VIS wavelength band is selected from 0.4 μm to 1.2 μm to contribute to photovoltaic (PV) conversion to generate electricity. Meanwhile, the IR band in longer wavelength ranges (1.2 μm ≤ λ ≤ 2.5 μm), which does not contribute to PV conversion, can be simultaneously used for solar thermal applications such as water heating and thermoelectricity. In this paper, various design parameters (e.g., focal length of a concentrating lens, groove density of a grating, geometry of dispersive prisms, material combination of optical components, etc.) have been investigated to determine an optimum set of system configurations, using optical design software (Zemax OpticStudio 14.2). Our simulation studies validate that the DOS is able to split incident AM1.5 solar irradiance into the two wavelength bands of the VIS and IR ranges and focus each wavelength band with concentration factors as high as 798× and 755× on the same focal plane, respectively. Such high concentration factors for both wavelength bands can be actualized due to the additional optical components used—a grating structure and dispersive prisms, which allow to minimize optical aberrations through both diffraction and refraction. The proposed DOS, designed with commercially available optical components, has the potential to widen the use of the sun’s spectrum by allowing effective PV conversion of solar cells under high concentration with tolerable optical system losses and concurrently converting the remaining solar irradiation into useful energy for a broad range of thermal applications.

Method for evaluating ophthalmic lens based on Eye-Lens-Object optical system.

We propose an evaluation method to judge the fitting extent to ophthalmic lens for the individual wearer. An Eye-Lens-Object optical system is set according to wearer's visual performance and the characteristic of ophthalmic lens assembly. A visual reference surface is proposed to calculate the object distance. The RMS radius of the spot diagram and MTF average value from optical design software Zemax are regarded as the criterion of assessing the image quality on the retina. Three cases are simulated to verify that our method is effective. The wearers can experience a comfortable wearing feeling when the evaluation method is used during the design of ophthalmic lens. The validity of our method is demonstrated to instruct designing the progressive addition lens with the freeform surface.

Minimizing aberrations of a near-infrared acousto-optic video spectrometer by optimizing the tunable filter parameters

Minimization of the aberration distortions of a near-infrared image spectrometer is addressed in this study. A model of an acousto-optical video spectrometer has been developed that provides a fairly high quality of spectral images over the 0.9–1.7 µm range. Aberration distortions are minimized through ZEMAX software, using a semi-automated (interactive) procedure to optimize the geometric parameters of an acousto-optic paratellurite cell with the selected parameters of other optical elements of the system. The prototype developed here is characterized by the absence of distortion and lateral chromatic aberration, with diffraction-limited spatial resolution of 30 µm in the image plane within the entire field of view. The resulting spectral images confirm the calculation and simulation results.