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arXiv · 1611.00874

Indirect Methods to Control Population Distribution in a Large Spin System

Lingfei Zhao·Maxim Goryachev·Jeremy Bourhill·Michael E. Tobar
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Abstract

We demonstrate how a large spin system ($S=7/2$) with the ground and the first excited state separated by a seven photon transition exhibit non equilibrium thermodynamic properties and how the population distribution may be manipulated using coupling between energy levels. The first method involves non-adiabatic passage through an avoided level crossing controlled with an external DC magnetic field and the resulting Landau Zener transition. The second method is based on external cavity pumping to a higher energy state hybridised with another state that is two single photon transitions away from the ground state. The results are confirmed experimentally with Gd$^{3+}$ impurity ion ensemble in a YVO$_{4}$ crystal cooled to 20 mK, which also acts as a microwave photonic whispering gallery mode resonator. Extremely long life times are observed due to large number of photons required for the transition between the ground and the first excited states.

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Lingfei Zhao, Maxim Goryachev, Jeremy Bourhill, Michael E. Tobar. 2016-11-03. Indirect Methods to Control Population Distribution in a Large Spin System. https://doi.org/10.1088/1367-2630%2Faa5fdd

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