Multiple-Quantum-Well CCD (Charge-Coupled Device) Spatial Light Modulators

摘要

Results are reviewed on the fabrication and operation of spatial light modulators which use electrosorption in multiple-quantum-well (MOW) structures. These devices are electrically addressed by clocking a pattern of charge packets into a charge-coupled device (CCD). At each CCD pixel the amount of stored charge determines the electric field across the underlying MOW structure, which in turn determines the optical transmission o the device near the band-edge quantum-well exciton peak. The light is incident normal to the wafer surface and enters the device through semitransparent CCD gates. Both 16-stage and 32-stage one-dimensional devices and 16-by-16 two-dimensional devices have been fabricated on epitaxial layers containing GaAs/A1GaAs MOW structures for operation in the 0.85-micrometer region and also on epitaxial layers containing InGaAs/GaAs MQW structures for operation above 0.9 micrometer. The one-dimensional devices have been operated as spatial light modulators at low CCD clock frequencies (up to 1 MHz); they display modulation depths far superior to CCD spatial light modulators fabricated on bulk GaAs. Keywords: Gallium arsenides; Aluminum Gallium arsenide; Charge coupled devices; Reprints; Spatial light modulators; Electroabsorption; Multiple quantum wells. (jhd)