All-optical acousto-optic effect

In conventional acousto-optic devices ultrasound signals are generated in a solid medium by applying an RF electrical signal to a piezoelectric transducer, which is bonded to the optical medium. However, it is well known that ultrasound can be generated in solids by using high power optical pulses incident on the medium. This offers the potential to perform acousto-optic modulation without the piezoelectric transducers and associated electronics. This method can be utilized to modulate a lower power laser beam using a second higher power laser source. Using femtosecond optical pulses, acousto-optic interaction in the terahertz regime becomes feasible. In this paper, these all-optical acousto-optic devices are utilized for signal processing applications. Some preliminary experimental results using laser generated ultrasound in different substrates will be given.