Diffraction element and method of manufacturing diffraction element

摘要

Provided is an immersion diffraction element that prevents decrease of diffraction efficiency thereof so as to satisfy optical performance. A reflection type diffraction element is made of a material transmitting a light, beam having a predetermined wavelength. An echelle diffraction grating covered with a reflecting film that prevents transmission of the light beam is formed on one surface of the material. A diffraction grating is formed off in a repeated manner, a blazed surface facing incident light and a non-blazed surface connecting the blazed surface to a neighboring blazed surface. An angle formed between the blazed surface and the non-blazed surface is an acute angle. A defect generated at a grating vertex of the blazed surface fails in a shadow of the neighboring blazed surface so as to prevent the incident light from becoming scattered light due to the defect portion.

主权项

1. A diffraction element, comprising:
a plurality of blazed surfaces formed on a brittle material, the plurality of blazed surfaces comprising a first blazed surface and a second blazed surface adjacent to the first blazed surface; a non-blazed surface connecting the first blazed surface and the second blazed surface; and a metal reflecting film formed on the plurality of blazed surfaces, wherein the diffraction element permits light to pass into the diffraction element and to be reflected by the metal reflecting film formed on the plurality of blazed surfaces so that beams of the light reflected interfere, by the plurality of blazed surfaces, with each other and pass out of the diffraction element for spectral separation of the light, wherein an angle formed between the non-blazed surface and the first blazed surface is an acute angle of 86° or more, and wherein a chip or crack formed between the non-blazed surface and the first blazed surface falls in a shadow of the second blazed surface.