10 GHz-class magneto-optic field sensing with bi-substituted rare-earth ion garnet rotation magnetization employed

We have experimentally investigated RF sensitivity and frequency response of the rotation magnetization (RM) based Faraday effect in a Bi-substituted rare-earth iron garnet plate, with the aim of exploring the possible implementation of an optical instrument for wideband magnetic field probing. We have pointed out and confirmed experimentally the effectiveness of applying an in-plane static magnetic field for the sensitivity enhancement of RM signal detection; the signal-to-noise ratio was improved by 40 dB or more. The RM frequency response is flat within a fluctuation of 2.5 dB from 10 MHz up to 3 GHz and its 3 dB bandwidth is as broad as 14 GHz. We have also proposed fiber-edge magneto-optic probe head structures which may provide the frequency response and sensitivity mentioned above.