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arXiv · 1611.09269

Negative free carrier absorption in terahertz quantum cascade lasers

C. Ndebeka-Bandou·M. Rösch·K. Ohtani·M. Beck·J. Faist
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Abstract

We analyze the peculiar case where the free carrier absorption arising from LO phonon absorption-assisted transitions becomes negative and therefore turns into a gain source for quantum cascade lasers. Such an additional source of gain exists when the ratio between the electronic and the lattice temperatures is larger than one, a condition that is usually fulfilled in quantum cascade lasers. We find a gain of few cm$^{-1}$'s at 200K. We report the development of a terahertz quantum cascade laser operating in the negative free carrier absorption regime.

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C. Ndebeka-Bandou, M. Rösch, K. Ohtani, M. Beck, J. Faist. 2016-11-28. Negative free carrier absorption in terahertz quantum cascade lasers. https://doi.org/10.1063/1.4942889

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