1. Giant optical polarisation rotations induced by a single quantum dot spin.
- Author
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Mehdi, E., Gundín, M., Millet, C., Somaschi, N., Lemaître, A., Sagnes, I., Le Gratiet, L., Fioretto, D. A., Belabas, N., Krebs, O., Senellart, P., and Lanco, L.
- Abstract
In the framework of optical quantum computing and communications, a major objective consists in building receiving nodes implementing conditional operations on incoming photons, using a single stationary qubit. In particular, the quest for scalable nodes motivated the development of cavity-enhanced spin-photon interfaces with solid-state emitters. An important challenge remains, however, to produce a stable, controllable, spin-dependent photon state, in a deterministic way. Here we use an electrically-contacted pillar-based cavity, embedding a single InGaAs quantum dot, to demonstrate giant polarisation rotations induced on reflected photons by a single electron spin. A complete tomography approach is introduced to extrapolate the output polarisation Stokes vector, conditioned by a specific spin state, in presence of spin and charge fluctuations. We experimentally approach polarisation states conditionally rotated by π 2 , π, and − π 2 in the Poincaré sphere with extrapolated fidelities of (97 ± 1) %, (84 ± 7) %, and (90 ± 8) %, respectively. We find that an enhanced light-matter coupling, together with limited cavity birefringence and reduced spectral fluctuations, allow targeting most conditional rotations in the Poincaré sphere, with a control both in longitude and latitude. Such polarisation control may prove crucial to adapt spin-photon interfaces to various configurations and protocols for quantum information.Light-matter interfaces implementing arbitrary conditional operations on incoming photons would have several applications in quantum computation and communications. Here, the authors demonstrate conditional polarization rotation induced by a single quantum dot spin embedded in an electrically contacted micropillar, spanning up to a pi flip. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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