“…A high photosensitivity in the visible range of spectra, high birefringence in conjunction with a wide transparency range of 0.5−14 µm make this crystal useful for optoelectronic applications [4]. For possible applications in optoelectronic device in the visible range, a great deal of attention has been devoted to the study of the structural [1,5,6], electrical [7][8][9], and optical [2-4, 8, 10, 11] properties. In this regard, detailed information on the presence of the impurity and defect centers in the crystal is very useful to fabricate high-quality devices.…”