Spectral Polarization Measurements by Use of the Grating Division-of-Amplitude Photopolarimeter

The grating division-of-amplitude photopolarimeter (G-DOAP) is an instrument that exploits the multiple-beamsplitting, 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 (sigma) and +/-0.1 ° in (DELTA), are demonstrated in the 550 -940-nm wavelength range.