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arXiv · 1408.2944

Strong Coupling between Whispering Gallery Modes and Chromium Ions in Ruby

Warrick G. Farr·Maxim Goryachev·Daniel L. Creedon·Michael E. Tobar
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Abstract

We report the study of interactions between cavity photons and paramagnetic Cr$^{3+}$ spins in a ruby (Cr$^{3+}$:Al$_2$O$_3$) Whispering Gallery mode (WGM) resonator. Examining the system at microwave frequencies and millikelvin temperatures, spin-photon couplings up to 610 MHz or about 5% of photon energy are observed between the impurity spins and high quality factor ($Q > 10^5$) WGM. Large tunability and spin-spin interaction allows operation in the strong coupling regime. The system exhibits behaviour not predicted by the usual Tavis-Cummings model because of interactions within the two-level spin bath, and the existence of numerous photonic modes.

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Warrick G. Farr, Maxim Goryachev, Daniel L. Creedon, Michael E. Tobar. 2014-08-13. Strong Coupling between Whispering Gallery Modes and Chromium Ions in Ruby. https://doi.org/10.1103/physrevb.90.054409

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