Coulomb enhancement of the third-order optical nonlinearities in quantum wells
M. Zal użny · Applied Physics Letters · 1992
The investigation of Khurgin and Li [Appl. Phys. A 53, 527 (1991)] on the electrostatic Coulomb enhancement of the third-order intersubband nonlinearities in stepped quantum wells is extended by taking into account the modification of the intersubband resonant energy by the depolarization effect. It was found that the ratio of the depolarization enhancement factor (ηd) to the electrostatic Coulomb enhancement factor (ηe) strongly depends on the shape of the quantum well. Obtained results show that, in the case of the conventional square quantum well, factor ηd is several times larger than ηe while in strongly asymmetric stepped quantum wells ηd≪ηe.