Polarization-spectroscopy measurement of the homogeneous linewidth of an inhomogeneously broadened color-center band

A polarized laser beam can bleach narrow, long-lived, anisotropic holes in the 607-nm zero-phonon line of the NaF N1 center. The width of these holes is twice the homogeneous linewidth, and three orders of magnitude less than the inhomogeneous width of the line. We report a polarization-spectroscopy technique which detects the dichroism and birefringence of the hole with better sensitivity than absorption spectroscopy. A simple rateequation model is developed to account for hole burning, but the recovery of the initial isotropic absorption profile appears to be a complex, slow, and intractable process. © 1980 The American Physical Society.