Device and method for measuring diffraction efficiency of a diffraction element

[0026] see figure 1 , is a structural schematic diagram of a measuring device for the diffraction efficiency of a diffraction element provided by the present invention, including: an interferometer 110, a diffraction element 120 and an optical power meter 130, the interferometer 110 selects a spherical standard mirror, and the interferometer 110 to The spherical wave focus position is R, and the distance between the interferometer 110 and the diffraction element 120 is S. in:

[0027] The laser beam emitted by the interferometer 110 enters the diffraction element 120 and is focused by the diffraction element 120 .

[0028] Further, the light in the test environment is turned off to minimize the interference of background light, and the background stray light energy is recorded by the optical power meter 130, and the count is E 0 .

[0029] When the laser beam emitted by the interferometer 110 enters the diffraction element 120, the optical power meter detects the total inciden

[0037] see figure 2 , a structural schematic diagram of a measuring method of a measuring device for the diffraction efficiency of a diffraction element provided by the present invention, comprising the following steps:

[0038] Step S110: Build an optical path, the optical path includes an interferometer, a diffraction element, and an optical power meter, the position of the interferometer to the spherical wave focus is R, the distance between the interferometer and the diffraction element is S, and the interferometer The outgoing laser beam enters the diffraction element and is focused after passing through the diffraction element.

[0039] Further, in order to ensure that the spherical wave emitted by the interferometer can cover the diffraction element 120, it is assumed that the distance from the focal point of the spherical wave emitted by the standard mirror of the interferometer is R, and the distance from the focal point to the diffraction element is S, which needs to s