Abstract
Yttrium aluminum garnet (YAG, Y3Al5O12) and yttrium aluminum garnet doped with neodymium (Nd:YAG) single crystals were grown by the Czochralski technique. The critical diameter and the critical rate of rotation were calculated. Suitable polishing and etching solutions were determined. As a result of our experiments, the transparent YAG and pale pink Nd:YAG single crystals were produced. The obtained crystals were studied by X-ray diffraction, Raman and IR spectroscopy. The crystal structure was confirmed by XRD. The 15 Raman and 17 IR modes were observed. The Raman and IR spectroscopy results are in accordance with X-ray diffraction analysis. The obtained YAG and Nd:YAG single crystals were without core and of good optical quality. The absence of a core was confirmed by viewing polished crystal slices. Also, it is important to emphasize that the obtained Nd:YAG single crystal has a concentration of 0.8wt.% Nd3+ that is characteristic for laser materials.
Highlights
Oxide materials are very interesting and they are being used more and more. They are used as laser materials, in nonlinear optics, acousto optics, for memorizing optical data and magnetic memories, wave guides, etc. [1,2]
Yttrium aluminum garnet (YAG, Y3Al5O12) and yttrium aluminum garnet doped with neodymium (Nd:YAG) are the most famous kind of oxide crystals widely used as the active medium in solid state lasers [3,4]
Nd:YAG crystals are usually grown by the conventional Czochralski (CZ) technique [5,6,7]
Summary
Oxide materials are very interesting and they are being used more and more. They are used as laser materials, in nonlinear optics, acousto optics, for memorizing optical data and magnetic memories, wave guides, etc. [1,2]. During the crystals growth process it is possible, according to the Czochralski’s method, to influence the shape of the liquid/solid interface through the growth parameters, such as both the growth and the crystal rotation rate, as well as the temperature gradient. Having started from the fact that inversion is determined by Reynold’s number, Brice together with Whiffin [23] established the dependence of a critical value (Re)c on previously mentioned parameters of growth and gave the following equation for the radius of inversion Rc. where A and B are constants which are to be experimentally determined, f – growth rate, G – temperature gradient. Kobayashi et al [29] studied numerically to obtain the critical crystal Reynold’s number at which the interface inversion occurs This phenomenon basically depends on the melt flow structure composed of free and forced convection caused by the crystal rotation rate [30]. The structural and optical properties obtained single YAG and Nd:YAG crystals were characterized using XRD, Raman and IR spectroscopy
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