Optical rectification in parabolic quantum wells, with an applied electric field, due to resonant inter-subband transitions is analyzed using a compact density-matrix approach. The large dipolar matrix elements obtained in such structures are partly due to the small effective masses of the host materials and are interpreted in terms of the participation of the whole band structure in the optical transitions. The other origin of the large optical rectification coefficient lies in the possibility of tuning independently the frequency ${\mathrm{\omega }}_0$ of the parabolic potential and the applied electric field F.

• Received 5 March 1993

DOI:https://doi.org/10.1103/PhysRevB.47.16322