Difference-harmonic generation in quantum dots

摘要

We investigate the prospects for difference-harmonic generation due to intersubband transitions in n-doped quantum dots. The third order susceptibility tensor is calculated for flat conic quantum dots, where the lateral size is significantly greater than the height. The energy levels and the dipole matrix elements associated with the intersubband transitions are obtained in the framework of the effective mass approximation, including a simple model for self-consistent screening in the dots. The spectral dependence of the susceptibility is calculated and the double-resonant enhancement of the response is considered. Numerical estimates of the efficiency of transformation of a two-colour near-IR pump indicate that it may be possible to observe a mid-IR output of the order of a milliwatt for the case of a muLti-QD-sheet structure placed in the center of a resonator.