Growth of Fibrous Single Crystals of Oxides by the Floating Zone Method

浮区法生长氧化物纤维单晶

• 批准号: 09650917
• 负责人: HIGUCHI Mikio
• 金额: $ 1.98万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650917/
• 关键词: fiber crystal; floating zone method; oxide; laser material; yttrium orthovanadate; dislocation density; ファイバー結晶; 小傾角粒界

In various optical devices, efficient laser oscillation or wavelength conversion is expected using a fiber crystal, in which laser beam is encapsulated. In this study, the floating zone method, which had been employed to grow bulk crystals, was applied to grow fiber crystals of oxides Neodymium-doped yttrium orthovanadeate (Nd : YVO_4), which has attracted the attention as a laser material with laser-diode pumping, was chosen as a model material. Growth conditions to obtain thinner crystals were examined and the relation between the crystal diameter and quality was clarified.To keep a stable molten zone, the feed diameter should be decreased with decreasing crystal diameters and the ratio of the feed diameter to the crystal one should be less than three. In the case of less than 1 mmphi. the ratio should be about two. To realize these conditions, a single crystalline feed rod with a uniform diameter was used by cutting and grinding after the zone pass. The minimum diameter obtained was 0.8 mm. Thinner crystals are expected by using a four-ellipsoidal type apparatus. Which has much higher convergence efficiency than in the present apparatus. A drastic decrease in dislocation density was found in the crystals below 3 mmphi, in which dislocations were spontaneously decreased with continuing crystal growth. The decrease in the thermal stresses because of the decrease in the crystal diameter would contribute to the quality improvement.In this study, a basic technique for growing fiber crystals of oxides by the floating zone method was established and the quality of the crystals was improved with decreasing crystal diameters. This technique is also applicable to grow other kinds of fiber crystals that were difficult to grow by the conventional methods.

在各种光学设备中，使用纤维晶体预期有效的激光振荡或波长转换，其中激光束被封装。在这项研究中，曾被用来种植大量晶体的浮动区方法，用于生长氧化氧化物媒体掺杂氧化物晶体的纤维晶体（ND：YVO_4），它以激光材料作为激光材料吸引了使用激光材料，并将其作为模型材料选择。检查了要获得较薄晶体的生长条件，并阐明了晶体直径和质量之间的关系。要保持稳定的熔融区域，应随着晶体直径降低而应降低饲料直径，而进料直径与晶体的比率应小于三。在小于1 mmphi的情况下。该比率应大约为两个。为了实现这些条件，通过切割和磨在区域后通过切割和研磨，使用了一个具有均匀直径的单晶进料棒。获得的最小直径为0.8毫米。通过使用四型型型设备，可以预期较薄的晶体。比目前的设备的收敛效率要高得多。在3 mmphi以下的晶体中发现了位错密度的急剧下降，其中随着持续的晶体生长，位错降低。由于晶体直径的降低，热应力的减少将有助于质量改善。在这项研究中，建立了通过浮动区方法生长的氧化物纤维晶体的基本技术，并且随着晶体直径的降低，晶体的质量得到了提高。该技术还适用于种植其他常规方法难以生长的其他类型的纤维晶体。