Detection of phase change of light using photorefractive liquid crystal and its application to laser ultrasonics

Laser ultrasonics using a photorefractive liquid crystal is investigated with coaxial- and counter-optical setups. The proposed laser ultrasonic method involves irradiating an object with a laser pulse to produce an ultrasonic vibration and then using another laser beam to detect the vibration. The phase of the laser beam reflected from the object is shifted by the ultrasonic vibration. By using liquid crystals with photorefractive properties, this phase shift can be detected. Compared to traditional laser ultrasonic methods, this system offers a simpler optical setup and allows for more precise measurements that are unaffected by environmental vibrations.