The invention discloses a method for
rapid imaging of absorption defect distribution on the surface of a large-
diameter optical element. The method comprises the following steps: carrying out collimation and beam expanding of high-energy pulse
laser to form a large-size excitation
light spot for
radiation heating on an optical element, enabling absorption defects on the surface and the subsurfaceof the optical element to be at
transient temperature distribution and
refractive index distribution; after certain time
delay, carrying out collimation and beam expanding of another beam of high-energy pulse
laser to form a large-size detection
light spot which penetrates through an identical area radiated by the optical element, and recording
diffraction light field distribution of the
light spot by using a CCD; controlling time
delay between excitation and detection
laser pulses and analyzing characteristics of
diffraction light field images recorded by using the CCD, thereby confirming whether the radiated area of the optical element has absorption defects or not and corresponding characteristics. By adopting the method, advantages that a conventional optical-thermal lens technique ishigh in detection sensitivity, high in resolution ratio, and the like are retained, a single-time detection area can be greatly increased, and
rapid detection on absorption defect distribution of large-
diameter optical elements is achieved.