We perform transmission spectroscopy on single quantum dots and examine the effects of a resident carriers spin, the incident laser spot size, polarization, and power on the experimental contrast. We demonstrate a factor of 4 improvement in the maximum contrast by using a solid immersion lens to decrease the spot area. This increase yields a maximum signal to noise ratio of 2000 Hz-1/2, which will allow for MHz detection frequencies. We anticipate that this improvement will allow further investigation of spectral fluctuation and open up the feasibility for an all-optical read-out of an electron spin in a quantum dot.
@article{arxiv.cond-mat/0701617,
title = {Contrast in transmission spectroscopy of a single quantum dot},
author = {B. D. Gerardot and S. Seidl and P. A. Dalgarno and M. Kroner and K. Karrai and A. Badolato and P. M. Petroff and R. J. Warburton},
journal= {arXiv preprint arXiv:cond-mat/0701617},
year = {2009}
}