| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve the accuracy of monitoring of a laser oscillation wavelength. <P>SOLUTION: An etalon filter includes a first transparent member and a second transparent member composed of glass or crystal, and a hollow member provided between the first transparent member and the second transparent member. A surface facing the hollow member, of the first transparent member and an opposite surface parallel to the surface are provided with a reflection coating, while the reflection coating is provided with a first joint film. A surface facing the hollow member, of the second transparent member and an opposite surface parallel to the surface are provided with a reflection coating, while the reflection coating on the side facing the hollow member is provided with a second joint film. Surfaces facing the first transparent member and the second transparent member, of the hollow member are provided with a third joint film. The first joint film and the third joint film are joined and the second joint film and the third joint film are joined. The internal hollow space of the hollow member is in an airtight state to keep vacuum or atmospheric pressure state. <P>COPYRIGHT: (C)2012,JPO&INPIT |
