Optically isotropic longitudinal piezoelectric resonant photoelastic modulator

Abstract

Photoelastic modulators are widely used optical instruments across many applications. Despite being in use since the 1960s, their design has remained largely unchanged. The main limitation of these modulators is the fundamental trade-off between the input aperture and the modulation frequency. These modulators typically operate around 50 kHz modulation frequency for centimeter square scale apertures. Optically isotropic and piezoelectric crystals, like gallium arsenide, gallium phosphide, zinc selenide, and zinc sulfide offer a groundbreaking opportunity to create new kinds of photoelastic modulators to overcome this trade-off. By adopting this new design, we can achieve both high modulation frequencies (in the megahertz frequency regime) and large input apertures (centimeter square scale) simultaneously.