In this work, a simple dielectric metasurface hologram is proposed and designed by combining the electromagnetic vector analysis method and the immune algorithm, which can realize the holographic display of dual wavelength orthogonal-linear polarization light in visible light band, solve the problem of low efficiency of the traditional design method of metasurface hologram, and effectively improve the diffraction efficiency of metasurface hologram. The titanium dioxide metasurface nanorod based on rectangular structure is optimized and designed. When the x-linear polarized light with wavelength of 532 nm and y-linear polarized light with wavelength of 633 nm are incident on the metasurface respectively, different display output images with low cross-talk can be obtained on the same observation plane, and the transmission efficiencies of x-linear and y-linear polarized light are as high as 68.2% and 74.6% respectively in simulation. Then the metasurface is fabricated by Atomic Layer Deposition method. The experimental results are consistent with the design results, which proves that the metasurface hologram designed by this method can completely realize the feasibility of wavelength and polarization multiplexing holographic display, and has potential application value in holographic display, optical encryption, anti-counterfeiting, data storage and other fields.

The metalens has vast applications in biomedicine and industrial manufacturing due to their ultrathin structure and vital ability to manipulate the properties of light waves for long-infrared systems. However, it is difficult for metalens to achieve the confocal function with high focusing efficiency, wide wavelength bandwidth, and low structural complexity. Here, we propose and experimentally demonstrate an all-silicon dielectric metalens composed of arrays of minimalist meta-atoms with a single rectangular nanopillar arranged on a periodic square lattice substrate, which realizes the confocal function of the orthogonal-linear-polarized light with wavelengths of 10.6 µm and 9.3 µm, with focusing efficiencies of 64.94% and 60.03%, respectively. Also, it reveals nearly the diffraction-limited focusing performance. In addition, the metalens can realize precise long-infrared thermal imaging. Moreover, the proposed metalens is compatible with the standard complementary metal oxide semiconductor processes, which can effectively reduce the manufacturing cost and provide a feasible solution for developing planar integrated multifunctional micro-nanophotonic devices in the long-infrared field.

The multi-channel perfect vortex (PV) array based on metasurface has important applications in optical communication, particle manipulation, quantum optics, and other fields due to its ultra-thin structure and excellent wavefront control ability. However, it is very challenging to utilize a single metasurface to simultaneously achieve independent channel PV arrays at different wavelengths with low crosstalk and low structural complexity. Here, we propose and design a single rectangular structured metasurface based on TiO₂, achieving a multi-channel PV beam array with dual-wavelength and dual-polarization multiplexing. Simulation and experimental results show that when two orthogonal linearly polarized beams with wavelengths of 532 nm and 633 nm are incident on the metasurface, clear PV arrays with corresponding topological charge arrangements can be obtained in different diffraction regions of the same observation plane. The metasurface proposed in this article can enhance the channel capacity of a PV beam array through wavelength-polarization-multiplexing, thus having important application potential in spatial information transmission, high-dimensional information storage, and secure information encryption.

The orbital angular momentum (OAM) multiplexing holography has the advantages of large information capacity and high security, and has important application value in holographic storage, optical encryption, and optical computing. However, as the number of multiplexing channels increases, this technology suffers from deterioration in image quality, which limits its application scope. This article proposes an innovative design that introduces an optical diffractive neural network (ODNN) into OAM multiplexing holography, establishes a scientific image quality evaluation function, applies an end-to-end optimization method, and designs OAM multiplexing holograms in parallel, significantly improving the image quality of OAM holography. The design results show that compared to classical methods, the ODNN method proposed in this paper has improved diffraction efficiency and signal-to-noise ratio by 29% and 19%, respectively, and reduced mean square error and variance by 10% and 43%, respectively. Moreover, high-quality multi-channel OAM multiplexing holography has been achieved through experiments. The design method proposed in this article provides an efficient and practical way for future OAM multiplexing holographic technology to further enhance information capacity and improve security.

It is difficult for optical correlator to recognize the target with large rotation distortion by using existing filters. To solve this problem, a new neural network model is constructed based on the physical recognition process of planar integrated 2F optical correlator. The new optical filter is optimized by training the neural network. The planar integrated 2f optical correlator can output sharp correlation peaks by using the new filter to recognize targets with arbitrary rotation distortion. Compared with the traditional OTSDF filter, the average increase of correlation peak index is up to 1402.4%, while the recognition performance of distortion invariant is also better than the new NNCRF filter. The simulation and experimental results show that the optical filter designed in this paper can effectively solve the problem of weak recognition ability of optical correlator for rotating distortion targets, especially for large angle rotating distortion targets.

In this paper, an optical correlator which adopts planar integrated 2F structure and optimal tradeoff synthetic discriminant function filter is proposed to improve the system integration and the recognition ability. The specialized digital microlens is designed for the correlator to replace the physical lens. By the theoretical analysis, the structural design conditions and parameters of the correlator are given, and the system volume is 63.1 cm ³ which is only half of the planar integrated 4F optical correlator. Moreover, simulations and experimental research works reveal that the correlator can achieve stable recognition to the input object of distortion with scaling (52%, 150%), rotation (-50°, +42°), and existed scaling (72%, 130%) and rotation (-36°, +38°) simultaneously. Theoretical analysis and experimental results indicate that the planar integrated optical correlator with compact structure and high integration has good performance of distortion invariant recognition.