| Project/Area Number |
05555001
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
FUKUDA Tsuguo IMR,Tohoku Univ.Professor, 金属材料研究所, 教授 (30199236)
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| Co-Investigator(Kenkyū-buntansha) |
YAMASHITA Sadao NK & K co., LTD.Manager of Products Development Dept., 商品開発部長
SASAKI Takatomo Faculty of Eng., Osaka Univ.Professor, 工学部, 教授 (50029237)
岡野 泰則 東北大学, 金属材料研究所, 助手 (90204007)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥4,700,000 (Direct Cost: ¥4,700,000)
Fiscal Year 1994: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1993: ¥4,500,000 (Direct Cost: ¥4,500,000)
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| Keywords | Laser crystal / Growth of single crystal / Laser diode pumped solid state laser / Garnet crystal / Continuous charging Czochralski method / Crystal growth method for in-situ core doping / Disordered type laser / Control of dopants distribution / laser / crystal growth / optical application / garnet / カルシウム ガリウム ガーネット / 引き上げ法 / 選択ドーピング / 半導体励起レーザ |
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| Research Abstract |
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.
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