Spatial light modulation using electroabsorption in a GaAs charge-coupled device

Abstract

High-speed one- and two-dimensional spatial light modulation may be carried out using the electroabsorption (Franz-Keldysh) effect in a GaAs buried-channel charge-coupled device (CCD). For photon energies slightly lower than the energy gap, the transmission through or along the surface of a CCD structure may be controlled by the signal charge in the wells, through the change of electric field with charge. The modulator is thus electrically addressable and it promises optical quality sufficient for coherent applications. Experimental measurements on a specially designed GaAs CCD structure with semitransparent gates have verified the predicted performance.