Ultrafast all-optical polarization switching in Bragg-spaced quantum wells at 80K

Abstract

A polarization switch is demonstrated in Bragg-spaced quantum wells at 80K that exhibits a 0.6THz optical bandwidth with a contrast ratio greater than 30dB, a throughput of ∼4%, a switching fluence of 8μJ∕cm2, and a pulse-width-limited picosecond response time. In this device, switching is achieved by using large spin-dependent nonlinearities induced by a circularly polarized control pulse to alter the polarization state of a linearly polarized signal pulse.