Frequency-modulation polarization-spectroscopy detection of persistent spectral holes

Abstract

Frequency-modulation polarization spectroscopy was used to detect persistent and anisotropic spectral holes written in the 607-nm color center in irradiated NaF and in the 683-nm absorption in phthalocyanine free-base-doped polyethylene. The high sensitivity of the technique permitted holes to be detected that had been written with exposure times down to 100 μsec. A general theory of frequency-modulation polarization spectroscopy is developed and specialized to the case of linear pump polarizations. Rate-equation models are presented to describe the anisotropic hole-burning process in a material, such as NaF, for which the absorbing centers have a finite distribution of possible orientations and in amorphous materials for which the distribution is uniform. The erasure of anisotropic holes because of excitation by the probe beam is investigated both theoretically and experimentally. A particular geometry was found to minimize this erasure effect in NaF. © 1984, Optical Society of America.