Contrast in transmission spectroscopy of a single quantum dot

TL;DR

This study enhances transmission spectroscopy of single quantum dots by optimizing experimental parameters, achieving a fourfold contrast improvement and enabling high-speed, high-sensitivity spin state detection for quantum information applications.

Contribution

The paper introduces a method to significantly improve contrast in quantum dot spectroscopy using a solid immersion lens, facilitating faster and more sensitive spin read-out.

Findings

Fourfold increase in contrast with solid immersion lens

Maximum signal-to-noise ratio of 2000 Hz^{-1/2} achieved

Potential for MHz detection frequencies and spin read-out

Abstract

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.