Magneto-optical effects in a high-$Q$ whispering-gallery-mode resonator with a large Verdet constant.

We have studied magneto-optical effects in an optical whispering-gallery-mode resonator (WGMR) manufactured from a Faraday-rotator material with, to the best of our knowledge, the record quality factor ($Q = 1.45\times10^8$) achieved for such materials. We have experimentally measured the eigenfrequencies deviation amplitude under the application of an external magnetic field and demonstrated the polarization plane declination over the light path. An analytical model for arbitrary magnetic field geometries in magneto-optic birefringent WRMRs has been developed.