Tradeoffs between oscillator strength and lifetime in terahertz quantum cascade lasers

Chun Wang I. Chan, Asaf Albo, Qing Hu, John L. Reno

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23 Scopus citations


Contemporary research into diagonal active region terahertz quantum cascade lasers for high temperature operation has yielded little success. We present evidence that the failure of high diagonality alone as a design strategy is due to a fundamental trade-off between large optical oscillator strength and long upper-level lifetime. We hypothesize that diagonality needs to be paired with increased doping in order to succeed, and present evidence that highly diagonal designs can benefit from much higher doping than normally found in terahertz quantum cascade lasers. In assuming the benefits of high diagonality paired with high doping, we also highlight important challenges that need to be overcome, specifically the increased importance of carrier induced band-bending and impurity scattering.

Original languageEnglish
Article number201104
JournalApplied Physics Letters
Issue number20
StatePublished - 14 Nov 2016
Externally publishedYes

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© 2016 Author(s).


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