THz quantum cascade lasers with output power over 1 W

Terahertz (THz) frequency radiation has many potential applications, ranging from imaging and chemical sensing through to telecommunications. However, one of the principal challenges is to develop compact, low-cost, efficient THz sources. In this respect, the development of the THz quantum cascade laser (QCL) has provided a potential solid-state solution. Nonetheless, for many remote sensing and imaging applications, high THz powers are desirable, in part owing to the significant attenuation of THz radiation by water vapour in the atmosphere. THz QCLs have been demonstrated with peak pulsed output powers (Ppeak) of up to 470 mW per facet, using a direct wafer-bonding technique to stack two separate THz QCLs together. This approach, however, requires the QCL to have a symmetric active region, limiting widespread applicability of the technique. In general, increased output powers in semiconductor lasers can be obtained by using longer and/or broader area cavities. Indeed, in long-cavity 4.7-THz QCLs, a Ppeak of up to 875 W (from both facets) was recently achieved. Here, we demonstrate THz QCLs with a Ppeak of 1.01 W from a single facet at 10 K by using a broader area device. The devices operate in pulsed mode with an emission frequency of around 3.4 THz. To the best of our knowledge, this is the first demonstration of THz QCLs with Ppeak exceeding 1 W.