Abstract
The optical properties of a recently discovered laser-active color center in oxygen-doped NaCl are reported. The color center is produced through a two-step photoaggregation process in additively colored crystals. Optical spectroscopy indicates that the point defect is a perturbed center. The center has very broad absorption and emission bands peaking at 1.09 and 1.55 μm, respectively, with a dipole moment oriented along the 〈110〉 directions of the crystal. The center population can be fully aligned along any 〈110〉 direction by using two-photon pumping. Ground- and excited-state absorption spectra compare well with the dielectrically embedded model for the eight transitions observed. uv spectroscopy has identified the substitutional ion as being the necessary impurity for the center formation. The proposed model for the color center is an -perturbed defect. The perturbing ion serves both as a stable electron trap as well as a spatial trap for the center.
- Received 23 December 1986
DOI:https://doi.org/10.1103/PhysRevB.35.7636
©1987 American Physical Society