Fluxing agent for crystal growth and crystal growth method

Abstract

The invention discloses a fluxing agent for crystal growth and a crystal growth method. The crystal is Pb17O8Cl18, and a system of the fluxing agent comprises at least one of PbO, metal halide M'X, metal halide M''X2 and Bi2O3; wherein M' is Li, Na or K, M'' is Mg, Ca, Ba, Sr or Pb, and X is F or Cl. The crystal growth method comprises the following steps: mixing and melting a polycrystalline rawmaterial and the fluxing agent; starting seeding above a melt temperature saturation point, stabilizing the melt temperature at the saturation point, and starting crystal growth; and growing the crystal to a required size, lifting the seed rod crystal to be separated from the liquid level, and carrying out annealing treatment in a weak oxidizing atmosphere. According to the method, the crystal growth orientation is fully considered, the crystal growth stability is effectively improved, the solution volatilization and system viscosity in the growth process are reduced, the problems of needle-like growth of the crystal, easy cracking and color change of the grown crystal and the like are solved, and the grown crystal is large in size and high in optical quality.

Description

technical field [0001] The invention relates to a single crystal growth method, in particular to a mid-infrared nonlinear optical Pb 17 o 8 Cl 18 A flux for crystal growth and a crystal growth method. Background technique [0002] Pb 17 o 8 Cl 18 The crystal is a new type of mid-infrared nonlinear optical crystal with high laser damage threshold discovered in 2015. It has the advantages of large nonlinear optical coefficient, high laser damage threshold, wide light transmission range, and stable physical and chemical properties. Compared with other mid-infrared nonlinear optical crystals, Pb 17 o 8 Cl 18 The growth habit of the crystal is good, and it can grow in an open system, which greatly reduces the difficulty of growing traditional infrared frequency-doubling crystals in a closed system. Pb 17 o 8 Cl 18 The crystal can realize mid-to-far infrared laser output for visible light or near-infrared laser through laser frequency conversion. Since the crystal has...

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Problems solved by technology

Due to Pb 17 o 8 Cl 18 The crystal is a molten compound with the same composition. The previous report used the method of spontaneous nucleation for crystal growth, but the grown crystals are all partially transparent, and there are a large number of macroscopic inclusions in the crystal. The grown crystal is easy to crack, which is difficult to meet Physical property test