Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 25: Quantum dots: Microcavities and microlaser

HL 25.1: Talk

Tuesday, March 17, 2015, 09:30–09:45, EW 203

Towards a high-cooperativity strong coupling of a quantum-dot in a tunable microcavity — •Sebastian Starosielec, Lukas E. Greuter, Andreas V. Kuhlmann, and Richard J. Warburton — University of Basel, Departement of Physics, Switzerland

An enhanced interaction between photons and quantum emitters offers a rich field of quantum applications, including single photon transistors and emitter-emitter coupling. Tailoring the vacuum properties of high-Q, low mode-volume optical resonators facilitates this enhanced interaction and ultimately allows a coherent and reversal exchange of energy quanta, challenging to achieve at optical frequencies in solid-state system. We investigate this strong coupling regime of an InGaAs/GaAs quantum dot with a high-finesse tunable microcavity [1,2] by means of high resolution laser spectroscopy with a polarization-based dark-field detection [3] under weak resonant excitation. High signal-to-noise spectra show a clear anti-crossing feature with state-of-art exciton/cavity cooperativity (C=5.5). Analyzing the resonance lineshapes, a spurious dispersive contribution to the exciton resonance is identified. In all likelihood a spectral fluctuation rather than a true decoherence process, the dephasing effect reduces the cooperativity from a bare value of C=9.1. Aiming for the high-cooperativity regime, besides a high-Q cavity and low mode-volume, we stress the point that equal efforts need to be taken towards lifetime-limited emitter linewidths.
R. J. Barbour et al., J. Appl. Phys. 110, 053107 (2011)
L. Greuter et al., Appl. Phys. Lett. 105, 121105 (2014)
A. V. Kuhlmann et al., Rev. Sci. Instrum. 84, 073905 (2013)