We report what is believed to be the first observation of phase conjugation by stimulated Brillouin scattering (SBS) in TeO<sub>2</sub> single crystal. The observed very low threshold for phase-conjugate mirror (PCM) formation, high PCM reflectivities in this initial experiment, and commercial availability of material hold promise for a host of practical applications in the near future. The resultant steady-state gain parameter, ~100 cm/GW, is to our knowledge the largest ever reported for any SBS material.
Mark A. Dubinskii and Larry D. Merkle, "Ultrahigh-gain bulk solid-state stimulated Brillouin scattering phase-conjugation material," Opt. Lett. 29, 992-994 (2004)