We demonstrate a novel all-optical spatial light modulator capable of megahertz modulation rates. It is based on the quantum-confined Stark effect, but the modulating electric f ield is entirely photogenerated by strongly asymmetric photocarrier transfer in GaAs/AlAs layers. In a nonoptimized sample, cw optical excitation of approximately 50 W/cm2 created a 30-kV/cm electric f ield, inducing a 9-meV exciton red shift at room temperature. Under pulsed excitation the photogenerated electric f ield can be switched on in a few tens of picoseconds and relaxes in a few hundred nanoseconds, permitting megahertz modulation rates.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics