RESONANT PHOTODIFFRACTIVE EFFECT IN SEMI-INSULATING MULTIPLE QUANTUM-WELLS

We use semi-insulating multiple quantum wells to combine the holographic properties of the photorefractive effect with the large resonant optical nonlinearities of quantum-confined excitons. GaAs-AlGaAs multiplequantum- well structures are made semi-insulating by proton implantation. The implant damage produces defects that are available to trap and store charge during transient holographic recording by means of coherent excitation. The advantages of charge storage and resonant optical nonlinearity combine to produce new optical devices with large sensitivities. The potential use of these devices for image processing is demonstrated by using the Franz-Keldysh effect in four-wave mixing at wavelengths near 830 nm. © 1990 Optical Society of America.