Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 18: Focussed Session: Strong Light Matter Coupling I

HL 18.6: Vortrag

Dienstag, 23. März 2010, 11:45–12:00, H13

Resonantly probing micropillar cavity modes by photocurrent spectroscopy — •Caroline Kistner, Stephan Reitzenstein, Kai Morgener, Christian Schneider, Sven Höfling, Lukas Worschech, and Alfred Forchel — Universität Würzburg, Technische Physik, Am Hubland, 97074 Würzburg

Compared to simple optically excited structures electrically contacted high-quality (high-Q) quantum dot-micropillar cavities provide an additional degree of freedom to either control the emission properties of the system via the quantum confined Stark-effect or to read out its optical properties by means of photocurrent (PC) spectroscopy [1,2]. This has particular implications when probing the system under strict resonant optical excitation where stray light from the excitation laser is a critical issue in resonance fluorescence studies. Here, we demonstrate the feasibility of detecting the cavity mode patterns of high-Q micropillars via PC spectroscopy. In particular, we resonantly probe the cavity resonances of electrically contacted micropillars by scanning the wavelength of the light incident on the top facet of the device and simultaneously measure the PC through the p-i-n structure using lock-in technique. At the cavity mode resonances of the micropillar the incident photons can efficiently enter the stop-band of the distributed Bragg reflectors, thus leading to an enhanced absorption of the light in the quantum dot layer which is reflected in pronounced resonances in the PC. The PC spectrum is in very good agreement with the mode spectrum obtained from micro-photoluminescence measurements.