Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 18: Focussed Session: Strong Light Matter Coupling I

HL 18.9: Hauptvortrag

Dienstag, 23. März 2010, 12:30–13:00, H13

Novel polariton-based devices: Room temperature polariton laser and electrically controlled polariton parametric amplifier — •Gabriel Christmann, Stavros Christopoulos, Christopher Coulson, and Jeremy J. Baumberg — NanoPhotonics Centre, Department of Physics, University of Cambridge, CB3 0HE, UK

Semiconductor microcavities (MCs) offer a unique system for producing novel types of non linear devices. In such systems polariton parametric amplification as well as polariton lasers can be obtained. These properties combined with the recent demonstration of electrical injection of polaritons offer a great potential for device realization.

Room temperature polariton lasers will be first presented. Here such systems are fabricated from lattice-matched monolithic GaN-based multilayers, including both bulk and QW microcavities. Coherent emission with a threshold below exciton saturation density is demonstrated in both types of structures. These devices offer a new route to robust long-lived GaN lasers and also provide a new prototype system for the study of macroscopic coherent states.

Then, recent results on a biased GaAs polariton light emitting diode structure will be presented. Pump probe experiments in the parametric amplifier geometry have been performed exhibiting up to 100 fold gains. By varying the electric field across the cavity, a very strong (>90%) quenching of the optical gain is observed for a sharp resonance. This effect is ascribed to competition between the rate of Rabi-coupling and of electronic tunnelling between adjacent quantum wells and is of high potential for the realization of novel light modulators.