Optical path structure for concave grating diffraction efficiency tester

The invention discloses an optical path structure for a concave grating diffraction efficiency tester and belongs to a concave grating diffraction efficiency tester in the technical field of light spectrum. The invention provides an optical path structure for a concave grating diffraction efficiency test to solve the technical problem, and the technical scheme for solving the technical problem is that: the structure comprises a light-source external optical path, a front monochromator, a measuring monochromator and a controller, wherein the light of the light-source external optical path is reflected by a condenser outside a shell of the front monochromator, is focused at an entrance slit and is transmitted into the front monochromator; emergent rays are transmitted into the measuring monochromator through an optical fiber; the measuring monochromator mainly comprises an incident optical arm, an emergent optical arm, an optical grating turntable and a photomultiplier; a standard concave mirror and a tested concave grating are successively arranged on the optical grating turntable for measurement; and the photomultiplier successively receives the reflecting luminous flux of the standard concave mirror and the diffraction luminous flux of the tested concave grating so as to finish the diffraction efficiency measurement of the concave grating. The optical path structure is simple and practical.