The invention discloses a device for measuring the
diffraction efficiency of an intermediate
infrared blazed grating, and the device comprises a tunable intermediate
infrared testing
laser, a guide
laser, a polarization device, a polarization light splitting device, a to-be-measured optical
grating, a three-dimensional electric displacement platform, an
optical detector, an attenuation piece, and a
spectrometer. An intermediate
infrared optical
grating causes the differences of first-order
diffraction output power of intermediate infrared
laser with different wavelengths, different incident angles and different polarization characteristics, so the device carries out the direct measurement of the
diffraction efficiency of the intermediate infrared optical
grating, and more truly reflects the actual
diffraction efficiency of the intermediate infrared optical grating in actual application. The device employs polarization light-splitting measurement and double-optical-path
detector comparison detection, and guarantees the
measurement precision. The device can achieve the
continuous measurement of the first-order spectrum
diffraction efficiency of the intermediate infrared optical grating.