Pick-up coil detection of the inverse Faraday effect in Tb-doped aluminium-boron-silicate glass

Abstract

Using a pick-up coil detection technique with a pulsed light source and an adapted preamplifier concept, we have measured the magnetization induced by circularly polarized light due to the inverse Faraday effect (IFE) in Tb-doped aluminium-boron-silicate magneto-optical glass.The dispersion of the IFE has been investigated for the first time experimentally, and the comparison of the signals at the basic and second harmonic frequencies of the Nd:YAG laser shows good qualitative agreement with the theoretically predicted wavelength dependence. Our experimental setup has reached a sensitivity for the IFE detection of up to 0.2 nT at room temperature and has allowed the observation of the effect also in quartz. Comparative measurements on other crystals of different symmetry have led to particular observations: in materials with large electro-optical constants (related mainly to optical rectification, such as in lithium iodate and in KDP) the recorded signals may effectively mask the IFE, or simulate IFE, but partly with different selection rules.This suggests that the pick-up coil technique in those cases could rather be used for contactless detection of electro-optical effects. Finally, the question has been raised of whether, in suitable chiral crystals, the method might be sufficiently sensitive to observe the much weaker (of the order of 10-2 times smaller than the IFE) inverse magnetochiral birefringence.