When a light beam propagates through an ensemble of two-level quantum systems, the resonant interaction between these systems and the radiation field may be described by a complex susceptibility. Even if the medium is of a type ordinarily considered isotropic, the susceptibility will be a tensor. In this paper, explicit expressions for the elements of this tensor are derived from quantum-statistical mechanics. A physical explanation of the induced anisotropy is given, and the experimental conditions under which it can be neglected are described.
© 1971 Optical Society of America
Original Manuscript: February 12, 1971
Published: November 1, 1971
J. D. Macomber, "Optical Anisotropy Induced by Resonant Absorption or Amplification of Radiation," Appl. Opt. 10, 2506-2512 (1971)