Multifuntional Metasurface for a Miniaturized Reflection-Type Atomic Vapor Cell

This paper reports the design, fabrication, and characterization of the multifunctional metasurface with integrated optical functions as the beam deflector and the quarter-wave plate (QWP) that can be applied in a miniaturized reflection-type vapor cell used for the chip scale atomic clock (CSAC). Our fabricated metasurface achieved an accurate deflection angle with an efficiency of 59.3% and simultaneously converted the linear to elliptical polarization with a degree of circular polarization (DoCP) of 70.5%. In addition, a high transmittance of 94.7% was obtained by considering the material of the metasurface, for instance, hydrogenated amorphous silicon (a-Si:H).