The Variable-delay Polarization Modulator

摘要

Precise astronomical polarization measurements generally require the use of polarization modulation. We have developed a new modulator, the Variable-delay Polarization Modulator (VPM) which uses two modified Martin-Puplett interferometers to induce a physical path length difference between polarization components. This highly durable and efficient device can easily be adapted to a wide range of wavelengths and temperatures, making it well suited for air- and space-borne facilities. This paper discusses the basic modulator design and a comparison to the half-wave plate, as well as details of VPM tests conducted at the Submillimeter Telescope Observatory (SMTO).