Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 30: Poster 2

HL 30.41: Poster

Donnerstag, 8. September 2022, 11:00–13:00, P3

Ultrafast spectroscopy of single quantum dots utilizing synchronized GHz-Oscillators — •Valentin Dichtl, Michael Seidel, Gerhard Schäfer, and Markus Lippitz — Experimental Physics III, University of Bayreuth, Germany

Ultrafast transient absorption or reflection spectroscopy of single semiconductor quantum dots is a well established technique, typically based on laser oscillators with about 80 MHz repetition rate. The excited state lifetime of the emitter is however much shorter than the pulse separation in these experiments. Most of the time one thus waits for the next laser pulse.

Here we present a modified setup based on two synchronized Ti:Sa lasers operating at 1 GHz repetition rate and a line camera with a spectral rate of 127 kHz. Noise suppression is accomplished via double modulation using a field programmable gate array (FPGA) for synchronizing AOMs with the line camera.

We demonstrate the perturbed free induction decay of single AlGaAs quantum dots at temperatures below 20 K. The total integration time is less than three minutes – currently software limited.