Search

With the development of holography and nanomanufacturing technology, metasurfaces are playing an increasingly important role in the field of holography. We designed a silicon cylindrical structure based on the Huygens metasurface. By exciting the Mie electric dipole and magnetic dipole resonance of the silicon cylindrical structure, a high transmission efficiency of 84% can be achieved at a wavelength of 633 nm, and a full phase coverage of 0-2π can be obtained by adjusting the radius of the silicon cylindrical. We used the angular spectrum algorithm to obtain the phase distribution relationship between the object image and the metasurface, and designed the arrangement of the silicon cylinder metasurface. The simulation obtained a high-fidelity hologram, and the structure has a high transmission efficiency around the 633 nm spectrum. This method can realize metasurface holography with high transmission efficiency, and it can be applied in holographic imaging.

This paper proposes a learning model of basketball players structure based on the Bayesian network. By analyzing the data of NBA 's players, we complete the structural learning of basketball players network based on the +/- values of 5 resident players in the Portland Trail Blazers team. We finally obtain a winning and losing models for the five resident players of the Portland Trail Blazers team, and we make suggestions for coaches about player rotation based on the analysis of the models.

Volume holograms can achieve concentration of sunlight, but it has shortcomings such as small concentration angle, dispersion, and complex production process of the volume holography material, which is difficult to mass produce. This paper proposes a method based on the metasurface concentrating sunlight. We analyzed the mechanism of volume holographic light focusing by Kogelnik coupling wave theory, which is greatly limited by wavelength selectivity. Utilizing the metasurface control mechanism on the wave front phase, the array arrangement that meets the light concentrating effect was designed. Simulation analysis shows that the metasurface can achieve light concentration in the visible light band with low dispersion.

Volume holograms can record and reproduce three-dimensional object. Compared with planar holograms, volume holograms can improve the resolution, stereo perception and realism of anti-counterfeiting, and realize three-dimensional anti-counterfeiting. In order to improve the diffraction efficiency and anti-counterfeiting effect of volume holographic anti-counterfeiting, this paper proposes a reflection volume holographic three-dimensional anti-counterfeiting method based on photopolymer. The diffraction characteristics and influencing factors are analyzed by Kogelnik’s coupled wave theory. Based on Piazzolla’s monomer diffusion model, the effects of exposure energy and exposure intensity on refractive index modulation and diffraction efficiency were studied. The simulation results show that the reflection volume holograms can achieve a greater refractive index modulation, with higher diffraction efficiency, stronger wavelength selectivity, which enhances the effect of three-dimensional anti-counterfeiting.