THz metasurface quantum-cascade VECSELs are emerging as broadly tunable single frequency sources of THz radiation in the 1.5-5 THz range, which can deliver output powers of milliwatts to tens of milliwatts, while exhibiting high-quality beam patterns. In this paper we discuss the most recent results, and identify the challenges associated with scaling the QC-VESCEL metasurfaces to longer and shorter wavelengths. It will appear in a special issue of IEEE Journal of Microwaves to celebrate the 70th Anniversary of the MTT Society.

Anthony D. Kim, Christopher A. Curwen, Yu Wu, John L. Reno, Sadhvikas J. Addamane, and Benjamin S. Williams, “Wavelength scaling of widely-tunable terahertz quantum-cascade metasurface lasers,” IEEE Journal of Microwaves, vol. 3, pp 305-318, January 2023.