Saturday, November 9, 2019

Abstract-Sub-terahertz and terahertz generation in long-wavelength quantum cascade lasers



Kazuue Fujita, Shohei Hayashi, Akio Ito, Masahiro Hitaka, Tatsuo Dougakiuchi

https://www.degruyter.com/view/j/nanoph.ahead-of-print/nanoph-2019-0238/nanoph-2019-0238.xml

Terahertz quantum cascade laser sources with intra-cavity non-linear frequency mixing are the first room-temperature electrically pumped monolithic semiconductor sources that operate in the 1.2–5.9 THz spectral range. However, high performance in low-frequency range is difficult because converted terahertz waves suffer from significantly high absorption in waveguides. Here, we report a sub-terahertz electrically pumped monolithic semiconductor laser. This sub-terahertz source is based on a high-performance, long-wavelength (λ ≈ 13.7 μm) quantum cascade laser in which high-efficiency terahertz generation occurs. The device produces peak output power of 11 μW within the 615–788 GHz frequency range at room temperature. Additionally, a source emitting at 1.5 THz provides peak output power of 287 μW at 110 K. The generated terahertz radiation of <2 THz is mostly attributable to the optical rectification process in long-wavelength infrared quantum cascade lasers.

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