Measurement device and method for measuring damage threshold of reflector in real time by using femtosecond laser

The invention discloses a measurement device and method for measuring the damage threshold of a reflector in real time by using femtosecond laser. According to the measurement device and method of the invention, after incident laser is split, and one laser beam is adopted as main laser, and the other laser beam is subjected to frequency multiplication, and then is adopted as detection light; the main laser is emitted onto the surface of a reflector sample, if the reflector sample is damaged, plasmas are generated on the surface of the reflector sample; one part of the detection light carries plasma information, and the one part of the detection light which carries the plasma information and a part of the detection light which does not carry plasma information are subjected to interference, so as to generate interference stripes; the delay of the detection light is changed through a delay optical path; and the interference patterns of the main laser at different time points after the main laser is emitted onto the surface of the reflector sample are obtained, and therefore, the evolution process of plasmas generated on the reflector sample after the main laser is emitted onto the reflector sample can be obtained, and the damage situation of the reflector sample can be obtained through inversion. The measurement device and method of the invention can be used for monitoring the damage situation of a 0-degree reflector by femtosecond laser under different energy and different power densities in real time, and can be applied to damage threshold measurement in the optical coating field and are of guiding significance for the improvement of an improving method of a femtosecond reflector damage threshold.