Fig. 1. (a) Schematic diagram of compact optical design for laser frequency stabilization device. (b) Sub-wavelength grating structure diagram, with t = 290 nm, Λ = 441 nm, and w = 285 nm. (c) Optical image of the entire chip, with a white circle highlighting the position of the metasurface structure. The enlarged part shows the SEM image of the partial sub-wavelength grating.

Fig. 2. (a) Normalized reflectivity (blue curve) and transmissivity (red curve) of all-dielectric metasurface chip for polarization angle from 0° (TM) to 90° (TE) of incident light. Solid curve, calculation result; dot dashed curve, measurement result. (b) Ellipticity of the reflected light with incident polarization angle from 0° to 90°.

Fig. 3. (a) Ellipticity and (b) normalized reflectivity of the reflected light for θ varying from 0° to 90°. Solid curve, calculation result; dot dashed curve, measurement result. (c) Atomic spectra of ⁸⁷Rb : F_g = 1→F_e with θ changing from 0° to 50°. The curve shifted with a step of 0.04 in the y-axis to improve clarity.

Fig. 4. (a) Schematic diagram of the laser frequency stabilization device based on the metasurface with an atomic vapor cell, and the dashed blue box represents the common glass vapor cell and the metasurface chip. (b) Allan deviation for the stabilized laser, the locking point for ⁸⁷Rb : F_g = 1→F_e, and the laser instabilities in the free-running laser (blue) and the locked laser (red).