Crystals (Jan 2021)

Evaluation of Growth, Thermal, and Spectroscopic Properties of Er<sup>3+</sup>-Doped CLNGG Crystals for Use in 2.7 μm Laser

  • Kaiyang Tang,
  • Shawuti Yingming,
  • Jinggang Gai,
  • Zhongben Pan

DOI
https://doi.org/10.3390/cryst11020126
Journal volume & issue
Vol. 11, no. 2
p. 126

Abstract

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A series of optical-quality Er3+-doped calcium lithium niobium gallium garnet (CLNGG) single crystals with different Er3+ ion concentration (10, 15 and 30 at.%) has been grown by the Czochralski method. A comparative study of their structure, thermal, and spectroscopic properties is performed. Crystal structure was analyzed with X-ray powder diffraction (XRPD) and refined by the Rietveld method, results showing that the Er:CLNGG crystal possesses a cubic structure with space group Ia3¯d, and the lattice constants decrease linearly as the Er3+ concentration increase. The complete set of thermal properties were systematically studied for the first time. It has been found that all the thermal conductivities increase with temperature, indicating a glass-like behavior. Effect of Er3+ concentration on spectroscopic properties of Er:CLNGG crystals was studied. Results show that with the Er3+ concentration increase, the NIR fluorescence around 1600 nm weakens, while the Mid-IR fluorescence intensity around 2700 nm strengthens. Fluorescence lifetime of 4I13/2 decreased faster than that of 4I11/2 with the Er3+ concentration increase, which is beneficial for surmounting the “bottleneck” effect to achieve 2.7 μm laser. All the results show that CLNGG crystal with high Er3+ concentration is a potential candidate for the 2.7 μm laser.

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