Strong Coupling between Whispering Gallery Modes and Chromium Ions in Ruby

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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Cited by in corpus (7)

• Ultra-High Cooperativity Interactions between Magnons and Resonant Photons in a YIG sphere
• Molecular monolayer strong coupling in dielectric soft microcavities
• Single Photon Level Study of Microwave Properties of Lithium Niobate at milli-Kelvin Temperatures
• Spin thermometry and spin relaxation of optically detected Cr3+ ions in ruby Al2O3
• Evidence of Dilute Ferromagnetism in Rare-Earth doped YAG
• Collective Behaviour of Cr${}^{3+}$ ions in Ruby Revealed by Whispering Gallery Modes
• Magnetic sensitivity of the Microwave Cryogenic Sapphire Oscillator