I. Dinculescu,C.Logofatu, N. Mincu, B.Iliescu, Fluoride crystals for IR optics, grown by the PVGF method, Journal of Crystal Growth  Volume 198 (1999) 999-1004

Title: Fluoride crystals for IR optics, grown by the PVGF method

Abstract: Plasma vertical gradient freezing (PVGF) is a method for growing crystals from the melt in a vertical temperature gradient using a DC glow discharge heater. In particular, undoped crystals can be purified during growth because of the complex shape of the vertical temperature gradient. Standard samples of LiF and CaF2 single crystals grown by the PVGF method from material of 99.9% purity have the following parameters: (a) for lambda is an element of [2.5-5 mu m], average transmission coefficient is 97% for LiF and 92.5% for CaF2; (b) repeated (unlimited) pulse power density approximate to 218 w/mm(2) (1 pulse/min, pulse length = 350 mu s, lambda = 2.94 mu m) for LiF samples. CaF2, and LIF single crystals were grown in a nitrogen atmosphere at a pressure of 10(-1)-10(-2) Torr. They are used in laser optics. Some of these fluorides can be doped and used as active media, to0.

Keywords: crystal growth; IR optics; laser application

Author: C.E.A. Grigorescu