Polarization-multiplexed zoom Moiré metalens for edge-enhanced imaging.

Optical image processing with high operational efficiency has been applied as a pre-processing imaging system for image recognition. Edge-enhanced imaging as a high-efficiency optical image processing method is of great significance for feature extraction and target recognition. However, the edge-enhanced imaging system based on the 4F system and the spatial filter transforms mainly work under coherent light illumination conditions, without continuously zooming to track the spatial position of the target.

Efficient light field acquisition for integral imaging with adaptive viewport optimization.

Light field displays reconstruct 3D scenes through integral imaging. However, inefficient light ray acquisition degrades the visual experience, while the fixed position of the exit pupil limits viewer mobility. In this paper, we propose a novel light field acquisition method employing parallax mapping techniques, coupled with adaptive viewport optimization based on eye tracking data.

Tunable polarization-insensitive multifocal metalens based on an inverse design framework.

Multifocal metalenses are effective elements for longitudinal light field modulation and have important applications in long-focal depth imaging and three-dimensional display. However, the forward design method is subject to destructive interference generated by phase discontinuity, and cannot achieve high-efficiency, tunable multifocal metalenses. Therefore, we propose an efficient and tunable inverse design framework based on the adjoint method and gradient strategy, transforming light field modulation into mathematical optimization of nonlinear constraints.

Mapping-based design method for high-quality integral projection system.

A general method for designing an integral projection system is proposed, including optical design and digital preprocessing based on the mapping within the projection system. The per-pixel mapping between the sub-images and the integral projection image is generated by incorporating an integral projection imaging model as well as the ray data of all sub-channels. By tracing rays for sparsely sampled field points of the central sub-channel and constructing the mapping between the central sub-channel and other sub-channels, the efficient acquisition of ray data for all sub-channels is achieved.

Design of a curved-target ultrashort throw projector based on predistortion and illumination precorrection.

Ultrashort throw projector (UTP) technology has been a challenging research focus in the fields of large field of view and short-distance projection. In this paper, we propose a design method for a curved-target UTP based on image precorrection. A predistortion method (<1 ) using a radial basis function is presented to effectively correct irregular distortion.

Automatic control method for freeform surface shapes.

Designing freeform optics with high degrees of freedom can improve their optical performances; however, there are high requirements for controlling the surface shapes of such optics. Optical designers need to add constraints to the optimization process and make repeated adjustments to ensure the manufacturability of these shapes; this process is cumbersome and relies heavily on the experience of the designer. In this study, an automatic control method for freeform surface shapes is proposed.

Design of compact off-axis freeform imaging systems based on optical-digital joint optimization.

Using a freeform optical surface can effectively reduce the imaging system weight and volume while maintaining good performance and advanced system specifications. But it is still very difficult for traditional freeform surface design when ultra-small system volume or ultra-few elements are required. Considering the images generated by the system can be recovered by digital image processing, in this paper, we proposed a design method of compact and simplified off-axis freeform imaging systems using optical-digital joint design process, which fully integrates the design of a geometric freeform system and the image recovery neural network.

Design and fabrication method of holographic waveguide near-eye display with 2D eye box expansion.

Augmented reality near-eye display (AR-NED) technology has attracted enormous interests for its widespread potential applications. In this paper, two-dimensional (2D) holographic waveguide integrated simulation design and analysis, holographic optical elements (HOEs) exposure fabrication, prototype performance evaluation and imaging analysis are completed. In the system design, a 2D holographic waveguide AR-NED integrated with a miniature projection optical system is presented to achieve a larger 2D eye box expansion (EBE).

Design of an off-axis near-eye AR display system based on a full-color freeform holographic optical element.

In this Letter, we propose a design and fabrication method for a full-color augmented reality (AR) optical system based on a freeform holographic optical element (HOE). A point-by-point design method is proposed to generate the starting point of the system. Based on the preliminarily optimized system, the recording systems of the full-color HOE are designed.

Design method of imaging optical systems using confocal flat phase elements.

Imaging systems consisting of flat phase element such as diffractive optical element, holographic optical element, and metasurface have important applications in many fields. However, there is still a lack of generalized and efficient design methods of these systems, especially for systems with nonsymmetric configurations. We proposed a design method of imaging system consisting of flat phase elements based on confocal properties.

Stray light analysis and suppression method of a pancake virtual reality head-mounted display.

Pancake virtual reality head-mounted displays (VR-HMDs) have attracted the attention of researchers in both academia and industry because of the compact size and light weight. However, owing to the use of optical path folding, there exist various stray lights in the optical system, which seriously degrades user experience. In this study, we analyze the causes and effects of multiple types of stray light systematically and design a VR-HMD with low stray light, large exit pupil diameter (EPD), compact form and light weight.

Design, stray light analysis, and fabrication of a compact head-mounted display using freeform prisms.

It has been a challenge to design an optical see-through head-mounted display that is compact, lightweight, and stray-light-suppressed by using freeform optics. A new type of design based on freeform prisms is presented. The system consists of three optical elements and a micro-display.

Designing reflective imaging systems with multiple-surfaces-integrated elements using a Gaussian function freeform surface.

We propose a design scheme and method of a freeform off-axis reflective imaging system with multiple mirrors integrated into one element. The use of a multiple-surfaces-integrated element, described by the Gaussian basis functions freeform surface with local and nonsymmetric properties, significantly decreases the system complexity, as well as reduces the assembly and fabrication difficulty, and achieves high imaging performance. The design theory and process including the initial system design, surface conversion, and system optimization are demonstrated in detail.

Design method of a wide-angle AR display with a single-layer two-dimensional pupil expansion geometrical waveguide.

Waveguide near-eye displays (NEDs) consist of a planar waveguide combiner and a coupling-in projection system. A two-dimensional geometrical waveguide (TDGW) can achieve an ultra-thin, large exit pupil diameter (XPD), wide-angle NED. The design method of a single-layer TDGW is presented and discussed in detail in this paper.

Uniformity improvement of two-dimensional surface relief grating waveguide display using particle swarm optimization.

Augmented reality head-mounted displays (AR-HMDs) based on diffractive waveguides have been a challenging and rewarding research topic focusing on near-eye displays. The size of the exit pupil and uniformity of the image illuminance are two important factors that affect the display performance of the diffractive waveguide. In this paper, a novel method for optimizing high uniformity of two-dimensional (2D) diffractive waveguide is proposed.

Design of off-axis reflective imaging systems based on freeform holographic elements.

Holographic optical element (HOE) can be used in many areas in optics due to its characteristics of thin structure, flexible wavefront reconstruction/control ability and angular/wavelength selectivity. In this paper, we propose a design method of off-axis reflective imaging systems based on freeform HOEs, which are fabricated by freeform wavefronts. The freeform HOEs offer many degrees of design freedom and can correct the aberrations in nonsymmetric imaging systems.

Optical design and pupil swim analysis of a compact, large EPD and immersive VR head mounted display.

Virtual reality head-mounted displays (VR-HMDs) are crucial to Metaverse which appears to be one of the most popular terms to have been adopted over the internet recently. It provides basic infrastructure and entrance to cater for the next evolution of social interaction, and it has already been widely used in many fields. The VR-HMDs with traditional aspherical or Fresnel optics are not suitable for long-term usage because of the image quality, system size, and weight.

Off-axis reflective imaging system design with a conicoid-based freeform surface.

In this paper, we propose an off-axis reflective system design method based on a non-rotational symmetric conicoid-based freeform (CBF) surface description. The base description avoids complicated calculation of decenter and tilt when using the conventional conic expression, thus simplify the system modeling and optimization process, and it can reduce the number of coefficients that needed to represent mild freeform surfaces. A design method that includes the automatic initial system searching, preliminary optimization with rotationally symmetric surface deviation and fine-tuning with non-symmetric surface deviation is proposed.

Ultra-thin multifocal integral LED-projector based on aspherical microlens arrays.

Multifocal imaging has been a challenging and rewarding research focus in the field of imaging optics. In this paper, an ultra-thin multifocal integral LED-projector based on aspherical microlens array (MLA) is presented. A two-layer aspherical sub-lens with NA = 0.

Generating starting points for designing freeform imaging optical systems based on deep learning.

Deep learning is an important aspect of artificial intelligence and has been applied successfully in many optics-related fields. This paper proposes a generalized framework for generation of starting points for freeform imaging optical design based on deep learning. Compared with our previous work, this framework can be used for highly nonrotationally symmetric freeform refractive, reflective, and catadioptric systems.

Freeform beam splitting system design for generating an array of identical sub-beams.

Laser beam splitting by freeform optics is promising but less studied. Instead of directly forming a target spot array, we propose to first convert the input beam into a closely connected Gaussian sub-beam array. All the Gaussian sub-beams have the same optical field distributions which thus can produce identical discrete spots on the target plane.

Design method of wide field-of-view imaging systems using Gaussian radial basis functions freeform surfaces.

High optical performance systems with wide field-of-view (FOV) have important applications in remote sensing. The radial basis functions, which have a prominent local characteristic in surface description, have attracted much attention in recent years. In this paper, an effective design method for the wide FOV imaging system using Gaussian radial basis function freeform surfaces is proposed.

High-resolution fast mid-wave infrared compressive imaging.

In the mid-wave infrared (MIR) band, large detector arrays are extremely costly and technically difficult to be manufactured. Thus, it is difficult to obtain high-resolution images for a conventional MIR camera. Spatial compressive imaging can improve resolution.

Designing double freeform surfaces for large ray bending irradiance tailoring of extended LED sources.

Many illumination applications require redistributing the irradiance distributions of LED sources with large ray bending. The problem becomes even more challenging for a compact design where the LED size is no longer ignorable. We tackle this problem by simultaneously designing two freeform optical surfaces.

Compact integrator design for short-distance sharp and unconventional geometric irradiance tailoring.

A compact microlens array (MLA) integral homogenizer composed of a projection MLA, a condenser MLA, and a subimage array mask based on Kohler illumination is presented herein. By adopting the optimal design of an aspheric projection sublens, a short-distance integrator for unconventional geometric irradiance tailoring can be acquired. Compared with the traditional integrator, the integral lens is removed in the proposed integrator.