title: Automated spatially scanning ellipsometer for retardation measurements of transparent materials.
abstract: A highly sensitive and automated technique has been developed for measuring the birefringence in transparent optical materials. The spatially scanning modulated transmission ellipsometer maps the birefringence of a transparent material by probing it with a polarization-modulated He-Ne laser beam. Computer-controlled voltage biasing of a Pockels cell permits self-calibration and background subtraction of the system retardance. The technique is capable of resolving differential retardances as small as 0.1 nm (λ/6328) through a range of ±λ/2, where λ = 632.8 nm. Samples typically range in size from 50 µm to 10 cm in diameter within the sample plane and as much as 400 mm along the optical axis.
authors.forename: J E
authors.initials: JE
authors.lastname: Hayden
authors.forename: S D
authors.initials: SD
authors.lastname: Jacobs