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

A new scheme for generation of coherent radiantion 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 which are generated in the same active region and serve as a coherent drive for the infrared field. This mechanism for frequency self-conversion can work efficiently at room temperature and with injection current pumping. Due to the parametric nature of infrared generation the proposed inversionless scheme is especially promising for long-wvavelength (far-infrared) operation.