| 摘要 |
PURPOSE:To make the thickness of a thin layer of a sodium nitrate single crystal uniform by putting spacers between light transmitting optical members holding the thin layer between them. CONSTITUTION:The narrow gap between light transmitting optical members 100A, B is made sufficiently uniform by putting spacers SP between the members, and molten sodium nitrate is filled into the gap. The thickness of the molten sodium nitrate can be made sufficiently uniform, and the direction of the C- axis is accurately defined. The spacers are not corroded by sodium nitrate and do not change the quality of the sodium nitrate single crystal with lapse of time. The spacers are easily put between the light transmitting optical members, and a metal, an alloy or oxide thereof are preferably used as the material of the spacers. Ordinary optical glass or quartz glass is suitable for use as the light transmitting material. |
