Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 60: Poster II: Optical Properties, incl. Photonic Crystals and Ultrafast Phenomena

HL 60.25: Poster

Thursday, March 25, 2010, 18:00–20:00, Poster D1

Distribution of resonance fluorescence from excitons in quantum wells at different temperatures — •Gerolf K. G. Burau, Günter Manzke, Frank Kieseling, and Heinrich Stolz — Universität Rostock, Institut für Physik, Universitätsplatz 3, 18055 Rostock

Resonance fluorescence has been established as a valuable tool for the detection of excitons in quantum wells (QW) [1,2]. We have developed a setup using high numerical aperture objectives giving a spatial resolution of 650 nm at a wavelength of 812 nm of the exciting laser. This enables (i) the spectroscopy of single localized excitons, and (ii) an increase of the intensity of the laser spot by a factor of 50. The sample consists of a series of single QWs with varying well width. Even in highest quality QWs with large well width, the image of the excitation spot under resonant conditions shows a granular structure indicating the localisation of the exciton states.

Exciting any of these states resonantly with a 1 MHz line width single mode cw laser. The resultant resonant Rayleigh scattering could be observed with high spectral and spatial resolution. The spectra show a strong dependent excitation power and temperature. The origins these effects are discussed.

[1] Ch. Nacke et al., Eur. Phys. J. B 30, 303-312 (2002)

[2] D. Schwedt et al., physica status solidi (c) 3, 2477 (2006)