Dresden 2020 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 64: Poster II
HL 64.27: Poster
Thursday, March 19, 2020, 10:00–13:00, P1A
Fast switching of quantum dot photons in a Mach-Zehnder interferometer — •Fabio Rimek1, Pia Lochner1, Hendrik Mannel1, Arne Ludwig2, Andreas D. Wieck2, Martin Geller1, and Axel Lorke1 — 1Faculty of Physics and CENIDE, University Duisburg-Essen, Germany — 2Chair of Applied Solid State Physics, Ruhr-University Bochum, Germany
A Mach-Zehnder interferometer can be used to measure the coherence of a photon stream by a two-path experiment. In the ultimate limit of a single photon in the interferometer, it is also a realization for the so-called which-path experiment, where a single photon occupies both paths of the interferometer.
In this contribution, we will use single photons from a single self-assembled quantum dot in the Heitler regime with coherence lengths exceeding the dimensions of the interferometer to realize a time-resolved which-path experiment. A major challenge is an electro-optical polarization switch in the wavelength range of the photons from the self assembled InAs/GaAs quantum dots (∼950 nm). The polarisation switch should switch the photon polarisation faster than the photon residence time in the Mach-Zehnder interferometer. Depending on the polarization, the path can be determined in the interferometer. The switching of the polarization is caused by a superposition of two perpendicularly polarized waves, exhibiting a phase difference that can be varied by an electro-optic modulator (EOM).
The polarization is stabilized by an PID controlled feedback loop, which eliminates fluctuations of the phase due to other influences.