TY - JOUR T1 - Nonlinear response of quantum-confined electrons in nonparabolic subbands JF - Journal of Applied Physics Y1 - 1996 A1 - Markelz, A. G. A1 - Gwinn, E. G. AB -

We show that quantum confinement can dramatically alter the density-dependence of the third-order susceptibility, chi(NP)((3)) that arises from band nonparabolicity. Our results predict an oscillatory dependence of the efficiencies for third-harmonic generation and four-wave mixing on the subband occupation of quantum wells, and for narrow wells with high charge densities predict an enhancement over the bulk susceptibility. We also make a simple estimate of the fields required to saturate this nonparabolicity contribution to chi((3)). We discuss these results in light of recent experiments on third-harmonic generation from narrow-gap quantum wells at frequencies of similar to 1 THz, and show that nonparabolicity may not be the only nonlinearity contributing to the large chi((3)) observed. (C) 1996 American Institute of Physics.

VL - 80 SN - 0021-8979 N1 - 7 ER -