Resonant parametric generation of infrared radiation on intersubband transitions in low-dimensional semiconductor heterostructures

A new scheme for the generation of coherent radiation on the intersubband transition without population inversion between subbands is presented. The scheme is based on the resonant nonlinear mixing of the optical laser fields on the two interband transitions that are intracavity generated in the same active region. The two-wavelength lasing on the interband transitions can be achieved at a substantially lower threshold current than gain on the intersubband transition. This may ensure cw room-temperature operation. Due to the parametric, inversionless nature of generation, the lasers proposed are especially promising for long-wave length operation above 20 mum.