Centers In LiF Crystals Research Articles

EXPERIMENTAL STUDIES OF F3+ COLOR CENTERS IN LiF CRYSTAL

In this paper, we describe systematically some experimental results of the optical characters of the creaion of F3+ centers in LiF crystal by electron bombardment under different conditions. The relative density between F3+ and F2 centers are analysed from fluorescence spectra. The experimental results show that irradiation temperature plays an important role in the creation of F3+ and F2 centers and affects the relative density of F3+ and F2 centers. The main results are as follows: (1) Irradiation at liquid nitrogen temperature and then warming up to room temperature in the dark can create F3+ canters with high density, which can be seen from the fluoreseence spectra, as fluorescence of F3+ centers centered at 530 nm is much stronger than that of F2 center (670 nm) and fewer N centers and R centers are presented in absortion spectra. (2) From dynamic fluorescence spectra, it can be shown that in the samples irradiated at liquid nitrogen temperature, the density of F3+ centers increase rapidly when F2+ centers decays. But in the samples irradiated at room temperature the growth of F3+ and F2 centers are approximatly with the came rate. (3) We observd the band width and double pike structure of the fluorescence excitation spectra of F3+ and F2 centers.

Laser emission of F3+ color centers in LiF crystals at room temperature

Laser emission of F3+ color centers in LiF crystal at room temperature (RT) is reported here for the first time.

Double stimulated emission of mixed color centers in AN LiF crystal

Generation of double stimulated emission utilizing mixed F 3 +- F 2 centers in an LiF crystal at room temperature (RT) is reported for the first time.

Nonlinear optical phase conjugate effect caused by F2- color center in LiF crystals

We report the experimental observation of nonlinear optical phase conjugate (NOPC) effect caused by the resonant saturable absorption of F2- centers in LiF crystals. The experiment was performed by making use of degenerate four-wave mixing in the laser cavity. We also give the curve of the phase conjugate reflectivity versus the incident energy of the probe light.

Resonance phonon scattering on stable F 2 + centers in LiF crystals irradiated in the stressed state

The joint action of gamma irradiation and mechanical stress on the optical absorption spectra and thermal conductivity of LiF crystals has been investigated both theoretically and experimentally. Optimum irradiation doses and stress magnitudes for the stabilization and the efficient accumulation of F 2 + centers in LiF are determined. The intensity of the absorption band due to F 2 + centers is reduced by less than a factor of two in measurements a year apart. The expression for the cross section of resonance phonon scattering on F 2 + centers is obtained, and the parameters of the model of the center are determined. The temperature dependence of the thermal conductivity is calculated, and a bend in the κ(T) curve revealed atT≈3–5 K is explained.

Flashlamp-pumped color center laser

Stimulated emission from the F2 color centers in LiF crystals was observed when these crystals were pumped with noncoherent light at room temperature.

Intracavity spectroscopy utilizing lasers based on $F^-_2$ color centers in LiF crystals

A description is given of an intracavity spectroscopic system based on a laser utilizing F2- color centers in a crystal of LiF and operating in the free-running regime emitting at wavelengths in the range 1.1–1.25 μ. The color-center laser was pumped by a neodymium laser. The absorption spectra of water vapor, methane, and ammonia were recorded.

Optical transformation of F and F-aggregate color centers in LiF crystals

Optical transformation of F and F-aggregate color centers in LiF crystals

Tunable laser utilizingF2+color centers in LiF and a holographic selector

An efficient and continuously tunable laser was constructed utilizing F2+ color centers in LiF crystals. The laser had a holographic total-internal-reflection selector and it operated at room temperature at a high pulse repetition frequency. The tuning range was 0.85–1 μ for a line less than 0.06 nm wide. The efficiency of conversion of the energy absorbed in a crystal was about 10%.