Laser ultrasonic inspection apparatus

A laser ultrasonic inspection apparatus comprising:

• a first laser light source configured to irradiate a target with a first laser beam as a pulsed beam;
• and
• a laser interferometer configured having a second laser beam to detect a vibration of the target derived from ultrasonic waves induced in the target by irradiation with the first laser beam, wherein
• the laser interferometer includes
• a second laser light source configured to irradiate the target with the second laser beam,
• a light modulator configured to use a vibrator to modulate a frequency of the second laser beam,
• a photodetector configured to receive the second laser beam from the light modulator and the second laser beam from the target to output a light reception signal, and
• a signal processor configured to detect the vibration based on the light reception signal and a reference signal, and measure, based on the reference signal, an elapsed time from the first laser light source emits the first laser beam to the vibration is detected, and
• the vibrator is a signal source of the reference signal.