Design of a wide bandwidth achromatic metalens based on phase change material GST with aperture sharing

• Published in: Xibei Gongye Daxue Xuebao Vol. 41; no. 6; pp. 1229 - 1234
• Main Authors: LYU Shuyuan, MENG Fei, LUO Wenfeng, BAI Yuchi, WANG Rong
• Format: Journal Article
• Language: Chinese
• Published: EDP Sciences 01.12.2023
• Subjects: achromatic metalens; aperture sharing; crystallization rate; phase change materials
• ISSN: 1000-2758; 2609-7125
• DOI: 10.1051/jnwpu/20234161229

This paper proposes the use of aperture sharing synergistic operation in the structure of the metalens, together with the rational selection of the scattering unit size according to the linear relationship between the output phase and frequency of the scattering unit, and the selection of the slope of the phase variation with frequency, combined with the modulation of the phase change material Ge2Sb2Te5 crystallization rate m value, in the set wavelength band, for different wavelengths of incident light through the metasurface can produce a uniform phase distribution. The method is used to achieve a polarization-insensitive achromatic metalens in the 9.5-13 μm continuous wavelength band by adjusting the m value of the phase transition material Ge2Sb2Te5 crystallization rate and producing a phase distribution with a uniform focal length for different wavelengths of incident light passing through the metasurface. The simulation results show that the focal length of the achromatic metasurface varies by 3.57 μm i