Eur. Phys. J. B 55, 283-288 (2007)
https://doi.org/10.1140/epjb/e2007-00055-1

Linear and nonlinear intersubband optical absorptions in an asymmetric rectangular quantum well

¹ Department of Physics, Selçuk University, Konya, 42075, Turkey
² Department of Physics, Middle East Technical University, Ankara, 06531, Turkey

Corresponding author: ^a ikarabulut@selcuk.edu.tr

Received: 16 August 2006
Revised: 24 January 2007
Published online: 21 February 2007

Abstract

The linear and nonlinear intersubband optical absorptions in Al_xlGa_1-xlAs/GaAs/Al_xr Ga_1-xrAs asymmetric rectangular quantum well are studied within the framework of the density matrix formalism. We have calculated the electron energy levels and the envelope wave functions using the effective mass approach. In addition, we have obtained an expression for saturation intensity. It is shown that the parameters such as asymmetry and width of potential well not only shift the peak positions in absorption spectrum but also considerably modify their height. These results suggest that the absorption process can be easily controlled by the structure parameters of an asymmetric rectangular quantum well. Also, the incident optical intensity has a great effect on the total absorption spectrum. We have seen that the absorption peak is reduced by half when the optical intensity is approximately 0.8 MW/cm² for well width L=90 Å and β=0.5. Moreover, it is seen that the saturation intensity is quite sensitive to the structure parameters of an asymmetric rectangular quantum well. Thus, the results presented here can be useful for electro-optical modulators and photodetectors in the infrared region.