Non-linear optical processes involving excited subbands in laser-dressed quantum wires with triangular cross-section

• A quantum wire with triangle cross section under intense laser field is studied.
• The effective mass approximation and the finite element method are used.
• Conduction subbands strongly depend on the laser field parameter.
• THG, DC Kerr effect, and EA susceptibilities are changed by the laser field.
• Two polarizations of the pump light with respect to the laser field are discussed.

The conduction subband structure of a triangular cross-section GaAs/AlGaAs quantum well wire under intense laser field is theoretically investigated by taking into account a finite confining potential. The calculation of the subband energy levels is based on a two-dimensional finite element method within the effective mass approximation. It is shown that a transversally polarized laser field non-uniformly shifts the subband energy levels and could be used for tuning the intersubband transitions and altering the related optical susceptibilities. We found that the non-resonant laser field allows the magnification and the red- or blueshift of the third-order non-linear susceptibility peaks for particular polarizations of the pump light and proper laser parameter values. The effects of the laser dressing field on the intersubband third harmonic generation and quadratic electro-optical process are discussed.