Evidence for intrinsic Kerr bistability of high-Q microsphere resonators in superfluid helium F. Treussart, V. S. Ilchenko, J.-F. Roch, J. Hare, V. Lefèvre-Seguin, J.-M Raimond and S. Haroche Eur. Phys. J. D, 1 3 (1998) 235-238 Published online: 15 March 1998 DOI: 10.1007/s100530050087