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arXiv · 2110.02650

A chiral one-dimensional atom using a quantum dot in an open microcavity

Nadia O. Antoniadis·Natasha Tomm·Tomasz Jakubczyk·Rüdiger Schott·Sascha R. Valentin·Andreas D. Wieck·Arne Ludwig·Richard J. Warburton·Alisa Javadi
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Abstract

In nanostructures, the light-matter interaction can be engineered to be chiral. In the fully quantum regime, a chiral one-dimensional atom, a photon propagating in one direction interacts with the atom; a photon propagating in the other direction does not. Chiral quantum optics has applications in creating nanoscopic single-photon routers, circulators, phase-shifters and two-photon gates. Furthermore, the directional photon-exchange between many emitters in a chiral system may enable the creation of highly exotic quantum states. Here, we present a new way of implementing chiral quantum optics $-$ we use a low-noise quantum dot in an open microcavity. Specifically, we demonstrate the non-reciprocal absorption of single photons, a single-photon diode. The non-reciprocity, the ratio of the transmission in the forward-direction to the transmission in the reverse direction, is as high as 10.7 dB, and is optimised $\textit{in situ}$ by tuning the photon-emitter coupling to the optimal operating condition ($\beta = 0.5$). Proof that the non-reciprocity arises from a single quantum emitter lies in the nonlinearity with increasing input laser power, and in the photon statistics $-$ ultralow-power laser light propagating in the diode's reverse direction results in a highly bunched output ($g^{(2)}(0) = 101$), showing that the single-photon component is largely removed. The results pave the way to a single-photon phase shifter, and, by exploiting a quantum dot spin, to two-photon gates and quantum non-demolition single-photon detectors.

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Nadia O. Antoniadis, Natasha Tomm, Tomasz Jakubczyk, Rüdiger Schott, Sascha R. Valentin, Andreas D. Wieck, Arne Ludwig, Richard J. Warburton, Alisa Javadi. 2021-10-06. A chiral one-dimensional atom using a quantum dot in an open microcavity. https://doi.org/10.1038/s41534-022-00545-z

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