Enhancement of the Coupling Gain in GaAs-Liquid Crystal Hybrid Devices

Abstract

In this work the evanescent space-charge field generated in semi-insulating GaAs semiconductor substrates was used to reorient the liquid crystals molecules sandwiched between them to study the energy exchange in two-wave mixing experiments. We show that the two-beam coupling gain coefficient in hybrid devices is enhanced by a factor of ∼36 as compared to GaAs alone. The photorefractive gain coefficient reported here is the largest ever reported in semiconductors without the need of space-charge enhancing techniques such as externally applied fields or running gratings.