Laser-induced circular dichroism by a resonant circularly polarized pump optical field

The paper presents and discusses a generalization of the equations of laser-induced circular dichroism (LICD) derived for linear molecules. LICD for freely rotating molecules by a resonant circularly-polarized pump field is an optical analogue of the Faraday effect in isotropic media. Its fundamental formulae and existent conditions have been deduced using the density matrix theory with a two-level model and time-reversal arguments. The antisymmetric rotational polarizability and LICD of symmetric and asymmetric top molecules are studied concretely using perturbation theory and angular momentum algebra. The order of magnitude of LICD and the physical phenomena closely related with it have been discussed. The results show that the LICD effect is exhibited by all freely rotating molecules and may provide useful information on optical activity and antisymmetric polarizability.