Distributed feedback ring resonators for vertically emitting terahertz quantum cascade lasers

Surface-emitting distributed feedback terahertz quantum-cascade lasers in metal-metal waveguides.

Single-mode surface-emitting distributed feedback terahertz quantum-cascade lasers operating around 2.9 THz are developed in metal-metal waveguides. A combination of techniques including precise control of phase of reflection at the facets, and use of metal on the sidewalls to eliminate higher-order lateral modes allow robust single-mode operation over a range of approximately 0.35 THz. Single-...

Terahertz quantum cascade lasers with quasi-periodic resonators

We report simulations and experimental results of THz QCLs with quasi-periodic resonators based on a Fibonacci sequence. Terahertz quantum cascade lasers were first demonstrated in 2002 [1] and have since undergone rapid development. One of the most active areas of reasearch into these devices has been the development of devices emitting in a single longitudinal mode through the use of distribu...

Surface emitting ring quantum cascade lasers for chemical sensing

We review recent advances in chemical sensing applications based on surface emitting ring quantum cascade lasers (QCLs). Such lasers can be implemented in monolithically integrated on-chip laser/detector devices forming compact gas sensors, which are based on direct absorption spectroscopy according to the Beer–Lambert law. Furthermore, we present experimental results on radio frequency modulat...

Nanowire terahertz quantum cascade lasers

Lateral distributed-feedback gratings for single-mode, high-power terahertz quantum-cascade lasers.

We report on terahertz quantum-cascade lasers (THz QCLs) based on first-order lateral distributed-feedback (lDFB) gratings, which exhibit continuous-wave operation, high output powers (>8 mW), and single-mode emission at 3.3-3.4 THz. A general method is presented to determine the coupling coefficients of lateral gratings in terms of the coupled-mode theory, which demonstrates that large couplin...