Laser induced ultrasonic inspection apparatus

A laser induced ultrasonic inspection apparatus comprising:

• a head including a first laser light source configured to irradiates an object under inspection with pulse-shaped first laser light, a first signal generator configured to generate a pulse control signal used to set a repetition frequency of the first laser light, and a laser interferometer configured to use second laser light to detect vibration of the object under inspection that is derived from an ultrasonic wave induced in the object under inspection by the radiation of the first laser light;
• a moving stage at which the object under inspection is placed and which is configured to change a relative position of the object under inspection with respect to the head;
• and
• a second signal generator configured to generate a stage control signal used to control an operation of the moving stage,
• wherein the laser interferometer includes
• a second laser light source configured to irradiate the object under inspection with the second laser light,
• a light modulator configured to use a vibrator to modulate a frequency of the second laser light,
• a light receiver configured to receive the second laser light traveling via the light modulator and the second laser light traveling via the object under inspection, and output a light reception signal, and
• a signal processor configured to detect the vibration based on the light reception signal and a reference signal,
• the first signal generator is configured to generate the pulse control signal based on the reference signal,
• the second signal generator is configured to generate the stage control signal based on the reference signal, and
• the vibrator is a signal source of the reference signal.