No abstract

The dependence of the eigenstates of a high-finesse Fabry–Pérot cavity on intracavity circular phase anisotropies is shown to provide a very sensitive method to measure small Faraday rotations. The method is experimentally checked by measuring the Verdet constant of the air and a sensitivity of 10−10 rad is reported.

The spatial representation of the generalized potentials associated with the two eigenstates of a quasi-isotropic laser, in the frame of the Landau theory, predicts two different types of first-order phase transitions. The different dynamics of the corresponding vectorial bistabilities are confirmed by an experiment with a laser with two oscillating nondegenerate eigenstates. Polarization instabilities predicted in the first type of transition are experimentally shown.