Abstract

We report about high temperature comb operation of THz quantum cascade lasers. The extremely diagonal nature of the optical transition combined with low loss copper-based double-metal waveguides allow CW operation up to 105 K and CW power in excess of 5 mW measured at 80 K. Terahertz emission spanning up to 600 GHz together with a narrow beatnote indicate comb operation at 80 K and strong RF injection modifies clearly the laser spectrum up to 700 GHz spectral bandwidth. Such devices show as well robust harmonic mode locking behaviour and their comb state can be controlled by means of an external tuning element.

© 2020 The Author(s)