Magneto-induced 'bleaching' of an absorbing medium in an anisotropic laser cavity

摘要

We describe experiments and the corresponding theory of a helium-neon laser containing an optical absorber cell with pure neon, a Faraday rotator and a partial polarizer. The absorber can be modulated. Additionally, a longitudinal magnetic field H induces rotation of the polarization plane of light in the absorber. Modulated output power of the laser is observed. We find good qualitative agreement of the measured data with the theoretical expectation. Under certain conditions the laser system demonstrates unusual behaviour: the output modulation vanishes for a specific choice of H, i.e. the laser becomes insensitive to the presence of the intracavity absorber. The possible spectroscopic application of this effect is briefly discussed.