Theoretical investigation of infrared generation mechanism by quantum coherence in low-dimensional semiconductor heterostructures
低维半导体异质结中的量子相干红外发射机理理论研究

We present an infrared generation mechanism without population inversion between subbands in quantum well and quantum dot lasers. The infrared generation scheme is based on the resonant nonlinear mixing of the two optical laser fields. These two optical fields come from two interband transitions in the same active region and serve as the coherent drive for infrared field. This mechanism of frequency down conversion should work efficiently at room temperature with injection current pumping, not relying on any ad hoc assumptions of long-lived coherence in the semiconductor active medium. Under optimized waveguide and cavity parameters, the intrinsic down-conversion efficiency can reach the limiting quantum value corresponding to one infrared photon generated by one optical photon. Because the proposed infrared generation is parametric, the proposed scheme without population inversion is especially promising for long-wavelength infrared operation.