The application discloses a
laser cavity diagnosis device and method based on double-frame
delay synchronization phase shift, which comprises an excitation module and a detection module; the excitation module comprises a first
laser, a first 1 / 2 wave plate, a
polarization beam splitter prism, a
beam splitter, an energy meter, a convex lens and a water tank; the detection module comprises a second
laser, a
beam expander lens group, a second 1 / 2 wave plate, a second
polarization beam splitter prism, a third 1 / 2 wave plate, a first reflector, a second reflector, a fourth 1 / 2 wave plate, a third
polarization beam splitter prism, a third reflector, a fourth polarization
beam splitter prism, a first 1 / 4 wave plate, a first
imaging lens, a first micro-polarization camera, a second 1 / 4 wave plate, a second
imaging lens and a second micro-polarization camera. The application introduces a double-frame
delay method in the traditional synchronous phase shift interference, overcomes the defects of the existing cavity detection technology, and realizes the observation of the
instantaneous phase change in a single cavity pulsation period.