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arXiv · 1011.2682

Stroboscopic back-action evasion in a dense alkali-metal vapor

G. Vasilakis·V. Shah·M. V. Romalis
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Abstract

We explore experimentally quantum non-demolition (QND) measurements of atomic spin in a hot potassium vapor in the presence of spin-exchange relaxation. We demonstrate a new technique for back-action evasion by stroboscopic modulation of the probe light. With this technique we study spin noise as a function of polarization for atoms with spin greater than 1/2 and obtain good agreement with a simple theoretical model. We point that in a system with fast spin-exchange, where the spin relaxation rate is changing with time, it is possible to improve the long-term sensitivity of atomic magnetometry by using QND measurements.

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G. Vasilakis, V. Shah, M. V. Romalis. 2010-11-11. Stroboscopic back-action evasion in a dense alkali-metal vapor. https://doi.org/10.1103/physrevlett.106.143601

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