Material configurations forn-type silicon-based terahertz quantum cascade lasers

Design of n-type silicon-based quantum cascade lasers for terahertz light emission

The design of terahertz quantum cascade lasers based on electronic intersubband transitions in Ge/SiGe quantum wells is investigated. A detailed theoretical model of the conduction-band lineup of these heterostructures is first presented and used to show that large quantum confinement in the L valleys can be obtained with properly selected layer compositions and thicknesses. Computation of the ...

Nanowire terahertz quantum cascade lasers

Terahertz photonic crystal quantum cascade lasers.

We combine photonic crystal and quantum cascade band engineering to create an in-plane laser at terahertz frequency. We demonstrate that such photonic crystal lasers strongly improve the performances of terahertz quantum cascade material in terms of threshold current, waveguide losses, emission mode selection, tunability and maximum operation temperature. The laser operates in a slow-light regi...

Tall-barrier terahertz quantum cascade lasers

A terahertz quantum cascade laser is presented in which selectively placed pure AlAs barriers are used to reduce parasitic leakage currents to the conduction band continuum. The design is demonstrated to have improved temperature performance over a regrowth of the current Tmax 200 K record holder (181 K vs. 175 K). Strangely, it fails to lase below 70 K, which we attribute to negative different...

Terahertz Imaging with Quantum Cascade Lasers

Milliwatt average power terahertz quantum cascade lasers (THz-QCLs) combined with microbolometer focal plane array cameras allow for acquisition rates on the order of 1×10 6 pixels/s. This system enables real-time imaging in transmission and reflection modes with signal to noise ratios of >25 dB per pixel. While these system allow rapid imaging for fairly transparent samples, signal to noise ra...