Detection of phase change of light using photorefractive liquid crystals and their application to laser ultrasonics

Coaxial- and counter-optical setups for laser ultrasonics using a photorefractive liquid crystal were fabricated. In laser ultrasonics, an object is irradiated with a laser pulse to create an ultrasonic vibration, and then another laser beam is used 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, the resulting phase shift of the laser beam reflected from the material can be detected. Compared to traditional laser ultrasonic methods, this system offers a simpler optical setup and allows for more accurate measurements that are not affected by environmental vibrations.