1. Giant optical polarisation rotations induced by a single quantum dot spin
- Author
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E. Mehdi, M. Gundín, C. Millet, N. Somaschi, A. Lemaître, I. Sagnes, L. Le Gratiet, D. A. Fioretto, N. Belabas, O. Krebs, P. Senellart, and L. Lanco
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Science - Abstract
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 $$\frac{\pi }{2}$$ π 2 , π, and $$-\frac{\pi }{2}$$ − 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.
- Published
- 2024
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