Difference frequency terahertz quantum cascade laser

Abstract

The invention provides a difference frequency terahertz quantum cascade laser. The difference frequency terahertz quantum cascade laser comprises an active area, and the active area is located above asubstrate. The active area comprises multi-cycle bottom-up cascade quantum dot active layers, the quantum dot active layer in each cycle comprises a plurality of bottom-up InGaAs / InAlAs quantum well / barrier pairs and quantum dot insertion layers, one quantum dot insertion layer is inserted between every two InGaAs / InAlAs quantum well / barrier pairs, and each quantum dot insertion layer comprises astrain self-organized quantum dot InAs layer and a GaAs layer which is used for strain compensation. According to the difference frequency terahertz quantum cascade laser, the multi-cycle cascade quantum dot active layers are introduced, and based on the phonon bottleneck effect and the inhomogeneous broadening degree of quantum dots, the performance, such as power, conversion efficiency, tuningrange and threshold current density, of the difference frequency terahertz quantum cascade laser can be improved.

Description

technical field [0001] The invention relates to the technical field of infrared semiconductor optoelectronic devices, in particular to a difference-frequency terahertz quantum cascade laser. Background technique [0002] The terahertz THz band (30-300 μm) is between infrared and microwave, and the characteristic absorption peaks of many molecules are located in this band, which makes it have broad application prospects. For example, the collision frequency and plasma vibration frequency of many gas molecules at room temperature, and the rotation and vibration energy levels of many biological macromolecules are in the terahertz band, so important material information can be identified through terahertz spectroscopy, which is useful for drugs, explosives, etc. It can be used to detect and study the nonlinear dynamic process inside the substance; it can also be used for medical diagnosis through the unique response of biomolecules in this wave band. Moreover, THz waves have a ...

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