Investigation on practical use of disordered type new laser crystals

为了大直径、高质量钙铌镓石榴石（CNGG）单晶的批量生产和新型光电系统的研制，研究了CNGG单晶的生长条件和激光性能，测定了Nd^3+、Tm^3+和Er^3+等激光激活剂在CNGG单晶中的平衡分配系数，控制了晶体的均匀性，并且比其它石榴石晶体的大。还测定了CNGG单晶的精确全等熔体组成。证实了高掺杂和生长高质量晶体的可能性。由于CNGG单晶的熔化温度为1470 ℃，发现Pt坩埚可用于晶体生长。结果表明，Pt坩埚与Ir坩埚相比，在改变生长气氛和降低成本方面具有优越性，掺杂无序结构的CNGG单晶具有宽的吸收光谱和荧光光谱，可作为激光二极管（LD），特别是一维LD阵列泵浦的新型固体激光器基质。一维LD阵列泵浦Nd：CNGG单晶的输出激光功率超过了Nd：YAG的输出激光功率，并开发了能精确控制晶体成分的连续加料系统和能实现纤芯掺杂和多功能结构的新晶体生长方法，以便于实际批量生产。研究了坩埚及其周围结构的复杂结构和精确的生长条件，讨论了大尺寸晶体生长过程中出现扭曲现象的机理和起源。研究了避免这些现象的生长条件和炉内温度场。

Growth conditions of calcium niobium gallium garnet (CNGG) single crystals with large diameter and high quality, and those laser properties were investigated for the practical mass production and the creation of new opto-electronic system.The equilibrium distribution coefficients of lasing activators such as Nd^<3+>, Tm^<3+> and Er^<3+> in CNGG single crystals, were determined to control the uniformity of crystals, and were larger than those of other garnet crystals. The precise congruent melt composition of the CNGG single crystal was also determined. The possibility of high doping and the growth of high quality crystals were confirmed. Since the melting temperature of the CNGG single crystal was 1470ﾟC,Pt crucibles were found to be available for the crystal growth. Usefulness of Pt crucibles compared with Ir ones based on the high degree of varying the growth atmosphere and reducing the cost, was confirmed.Broad absorption and fluorescence spectra of doped CNGG single crystals based on the disordered type structure showed profitable properties as the new solid state laser host pumped by a laser diode (LD), especially by one dimensional LD array. The output laser power pumped by one dimensional LD array of Nd : CNGG single crystals exceeded that of Nd : YAG.Continuous charging system which enables the precise control of the grown crystal composition, and new crystal growth method which enables core doping and multi-functional structure, were also developed for the practical mass production. Complex structures of crucibles and surrounding constructions, and precise growth conditions were investigated.Mechanism and origin of twisting phenomena which appeared during the growth of large size crystals were discussed. The growth conditions and temperature fields of inside furnaces to avoid these phenomena were investigated.