Resonantly probing micropillar cavity modes by photocurrent spectroscopy

The investigation of quantum electrodynamics effects such as weak and strong coupling in quantum dot- micropillar systems in electrically contacted devices has recently become possible due to advances in nano- processing. This is of high interest for practical applications, e.g. the realization of compact single photon sources. Moreover, compared to simple optically excited structures electrically contacted high quality (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. This has particular implications when probing the system´s properties under strict resonant excitation where the elimination of stray light from the excitation laser is a critical issue in resonance fluorescence studies.