Fig. 1: Comparison between conventional and metasurface array-based spectroscopic ellipsometry.

a Schematics of a conventional spectroscopic ellipsometry system equipped with a compensator, a mechanically-rotating analyzer, and a grating-based multi-channel spectrometer. The thickness d and refractive index n of the thin film can be determined by fitting the measured ellipsometry parameters with a theoretical model. b Schematics of a metasurface array-based single-shot spectroscopic ellipsometry system. The metasurface array, with each unit cell designed to support anisotropic and spectrally-diverse response, is used to encode the full Stokes polarization spectrum of light reflected from the thin film onto a CMOS image sensor. The ellipsometry parameters can be computationally reconstructed and used to determine the thin film properties. CMOS complementary metal-oxide semiconductor