The grating division-of-amplitude photopolarimeter (G-DOAP) is an instrument that exploits the multiple-beam-splitting, polarizing, and dispersive properties of diffraction gratings for the time-resolved measurement of the complete state of polarization of collimated broadband incident light, as represented by the four Stokes parameters as a function of wavelength across the spectrum. It is a compact, high-speed sensor that has no moving parts and is simple to install and operate. These characteristics make the G-DOAP well suited for in situ spectroscopic ellipsometry (SE) applications for monitoring and controlling thin-film processes. The design and performance of a prototype instrument are presented. Precise SE measurements, to ±0.04° in ψ and ±0.1° in Δ, are demonstrated in the 550–940-nm wavelength range.
Shankar Krishnan, Scott Hampton, James Rix, Brian Taylor, and Rasheed M. A. Azzam, "Spectral Polarization Measurements by Use of the Grating Division-of-Amplitude Photopolarimeter," Appl. Opt. 42, 1216-1227 (2003)