Physical Review A
Normal-mode coupling of rare-earth-metal ions in a crystal to a macroscopic optical cavity mode
Kouichi Ichimura, Hayato Goto
Abstract
We demonstrated coupling of rare-earth-metal ions in a crystal to a macroscopic cavity mode by observing optical bistability and normal-mode peaks due to sweeping-laser-induced population redistribution of the ions. The experimentally evaluated coupling constant between the individual ions and the single cavity mode is $15\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$, which is comparable with or larger than the dissipation of the ions and will exceed the cavity dissipation with a narrowing of the mode waist of the cavity to the wavelength. The results advance the application of a coupled system of rare-earth-metal ions in a crystal and an optical cavity for quantum information processing.