Electrooptic effects in GaAs-AlGaAs narrow coupled quantum wells

摘要

The linear and quadratic electrooptic coefficients in narrownsingle and strongly coupled GaAs-AlxGa1-xAsnquantum wells have been measured. The quadratic electrooptic effect isnenhanced over that of conventional square quantum wells for both TE andnTM polarization in all the structures considered, by up to six times innthe case of 2-nm-wide GaAs-Al0.2Ga0.8As stronglyncoupled quantum wells. The origin of the enhanced quadratic electroopticneffect was found to correlate with a larger red shift in the absorptionnedge exciton and strong Coulombic coupling of the bound exciton statesnwith the quasi-continua