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arXiv · 1910.05430

Spin coherence and optical properties of alkali-metal atoms in solid parahydrogen

Sunil Upadhyay·Ugne Dargyte·Vsevolod D. Dergachev·Robert P. Prater·Sergey A. Varganov·Timur V. Tscherbul·David Patterson·Jonathan D. Weinstein
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Abstract

We present a joint experimental and theoretical study of spin coherence properties of 39K, 85Rb, 87Rb, and 133Cs atoms trapped in a solid parahydrogen matrix. We use optical pumping to prepare the spin states of the implanted atoms and circular dichroism to measure their spin states. Optical pumping signals show order-of-magnitude differences depending on both matrix growth conditions and atomic species. We measure the ensemble transverse relaxation times (T2*) of the spin states of the alkali-metal atoms. Different alkali species exhibit dramatically different T2* times, ranging from sub-microsecond coherence times for high mF states of 87Rb, to ~100 microseconds for 39K. These are the longest ensemble T2* times reported for an electron spin system at high densities (n > 10^16 cm^-3). To interpret these observations, we develop a theory of inhomogenous broadening of hyperfine transitions of ^2S atoms in weakly-interacting solid matrices. Our calculated ensemble transverse relaxation times agree well with experiment, and suggest ways to longer coherence times in future work.

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Sunil Upadhyay, Ugne Dargyte, Vsevolod D. Dergachev, Robert P. Prater, Sergey A. Varganov, Timur V. Tscherbul, David Patterson, Jonathan D. Weinstein. 2019-10-11. Spin coherence and optical properties of alkali-metal atoms in solid parahydrogen. https://doi.org/10.1103/physreva.100.063419

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