Laser radar receiving system based on micro-nano structure film diffraction optical element

The invention discloses a laser radar receiving system based on a micro-nano structure film diffraction optical element, and the system comprises a micro-nano structure film diffraction primary mirror which is used for focusing and outputting a large-angle optical signal incident from the front of a laser radar lens; the small hole is used for diffracting the output light of the primary mirror through the micro-nano structure film so as to control the receiving field visual angle of the laser radar receiving system; the collimation group is used for enabling the output light passing through the small hole to pass through so as to ensure that the output light enters the surface of the narrow-band optical filter in a normal direction; the narrow-band optical filter is used for filtering stray light of other wavelengths except the working wave band; and the convergence group is used for refocusing the light energy of the output light passing through the narrow-band optical filter to the photosensitive surface of