Thin THz QCL active regions for improved continuous-wave operating temperature

We compare the performance of 10 and 5 mu mthick metal-metal waveguide terahertz quantum-cascade laser ridges operating around 2.7 THz and based on a 4-well phonon depopulation active region design. Thanks to reduced heat dissipation and lower thermal resistance, the 5 mu m thick material shows an 18 K increase in continuous wave operating temperature compared to the 10 mu m material, despite a lower maximum pulsed-mode operating temperature and a larger input power density. A maximum continuous wave operating temperature of 129 K is achieved using the 5 mu m thick material and a 15 mu m wide ridge waveguide, which lased up to 155 K in the pulsed mode. The use of thin active regions is likely to become increasingly important to address the increasing input power density of emerging 2- and 3-well active region designs that show the highest pulsed operating temperatures. (c) 2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

By comparing the performance of 10 and 5 micrometer thick metal-metal waveguide terahertz quantum-cascade laser ridges, it was found that the 5 micron thick material has a higher continuous wave operating temperature and is becoming increasingly important in emerging designs.