Observation of the transition from lasing driven by a bosonic to a fermionic reservoir in a GaAs quantum well microcavity
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We show that by monitoring the free carrier reservoir in a GaAs-based quantum well microcavity under non-resonant pulsed optical pumping, lasing supported by a fermionic reservoir (photon lasing) can be distinguished from lasing supported by a reservoir of bosons (polariton lasing). Carrier densities are probed by measuring the photocurrent between lateral contacts deposited directly on the quantum wells of a microcavity that are partially exposed by wet chemical etching. We identify two clear thresholds in the input-output characteristic of the photoluminescence signal which can be attributed to polariton and photon lasing, respectively. The power dependence of the probed photocurrent shows a distinct kink at the threshold power for photon lasing due to increased radiative recombination of free carriers as stimulated emission into the cavity mode sets in. At the polariton lasing threshold on the other hand, the nonlinear increase of the luminescence is caused by stimulated scattering of exciton-polaritons to the ground state which do not contribute directly to the photocurrent.
Brodbeck , S , Suchomel , H , Amthor , M , Steinl , T , Kamp , M , Schneider , C & Hoefling , S 2016 , ' Observation of the transition from lasing driven by a bosonic to a fermionic reservoir in a GaAs quantum well microcavity ' Physical Review Letters , vol 117 , no. 12 , 127401 . DOI: 10.1103/PhysRevLett.117.127401
Physical Review Letters
© 2016, American Physical Society. This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at journals.aps.org / https://doi.org/10.1103/PhysRevLett.117.127401
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