Calculation of linear and nonlinear intersubband refractive-index changes in an asymmetrical semiparabolic quantum well with applied electric field

摘要

By using the displacement harmonic variant method and the compact density matrix approach, the linear and nonlinear intersubband refractive-index changes (RICs) in a semiparabolic quantum well (QW) with an applied electric field have been investigated in detail. Simple analytical formulae for the linear and nonlinear RICs in the system were also deduced. The effect of the band nonparabolicity has been taken into account. Numerical calculations of typical GaAs semiparabolic QWs were performed. The dependence of the linear and nonlinear RICs on the incident optical intensity, the frequency of the confined potential of the semiparabolic quantum well, and the strength of the applied electric field were discussed under both conditions of considering and ignoring the band nonparabolicity. Results reveal that the RICs in the semiparabolic quantum-well system sensitively depend on these factors. (c) 2005 WILEY-VCH Verlag GmbH B Co.