Phase transitions can change the crystal structure and modify the physical properties of crystals. In this work, we investigate the phase transition behavior in BaGaSe, an important middle infrared (mid-IR) nonlinear optical (NLO) crystal, in the temperature range from room temperature to 1173 K. Interestingly, the BaGaSe crystal undergoes a reversible ferroelastic phase transition at = 528 K, resulting in the presence of a newly discovered phase (γ-phase) at the higher temperature.
View Article and Find Full Text PDFLarge single crystals of LiGaGe2Se6 were grown, and their structure and linear optical properties were studied. According to XRD results there is some disorder because of the Li ion fluctuation and their redistribution along two cationic sites. The shape of the fundamental absorption edge versus temperature was analyzed, and direct band gap values were estimated from the Tauc plots.
View Article and Find Full Text PDFType-I phase matching for second-harmonic generation at 10.6 microm in LiGaTe(2) is demonstrated by using a tunable single-frequency continuous-wave CO(2) laser, and the nonlinear coefficient of LiGaTe(2) is determined from comparison with AgGaSe(2). The effective nonlinearity of LiGaTe(2) for this process amounts to 34.
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