| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission type diffraction grating having a groove pitch nearly the same as a transmission laminar type diffraction grating and a resolution higher than it. SOLUTION: A braze type diffraction grating 10 is adopted as the transmission type diffraction grating. A beam is made incident on a diffraction grating from the grating surface to be made emitted from the opposite surface. At this time, when the braze angleθof a grating groove is changed, the diffraction efficiency of diffraction beams of the number of each of order number changes according to that. Then, the braze angleθis decided so that the diffraction efficiency of the beams of the number of target orders of secondary or above or -secondary or below in a target wavelength range becomes maximum.
|
