The output power and beam divergence behaviors of tapered terahertz quantum cascade lasers

Nanowire terahertz quantum cascade lasers

High-Power Growth-Robust InGaAs/InAlAs Terahertz Quantum Cascade Lasers

We report on high-power terahertz quantum cascade lasers based on low effective electron mass InGaAs/InAlAs semiconductor heterostructures with excellent reproducibility. Growth-related asymmetries in the form of interface roughness and dopant migration play a crucial role in this material system. These bias polarity dependent phenomena are studied using a nominally symmetric active region resu...

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...