EXCITONIC RESONANT SELF-ELECTRO-OPTIC-DEVICE CONFIGURATION IN POLYTYPE DOUBLE-QUANTUM-WELL STRUCTURES

We consider a generic polytype double-quantum-well structure where it is possible to achieve a resonance between a spatially direct exciton (both the electron and hole are confined in the same well) and a spati ally indirect exciton that has the hole in the same Valence subband, b ut the electron localized in the other quantum well. Since the two exc itons are coupled through electron tunneling, the true excitonic eigen states are direct-indirect hybrids. We have calculated the nonlinear o ptical susceptibility of such a system, including both charge-transfer and many-body effects. We have applied our model to the polytype AlSb /InAs/AlSb/GaSb/AlSb structure. The hybrid excitons show enhanced opti cal nonlinearities because of the charge-transfer character of the ind irect exciton and the large oscillator strength of the direct one.