Acousto-optic effect
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The acousto-optic effect is a photoelastic effect generated by an ultrasonic wave in transparent optical material, usually fused silica, which couples the modulating strain field of the ultrasonic wave to the optical index of refraction. The amplitude of the refractive index change is proportional to that of the sound.
[edit] History
- Brillouin predicted the diffraction of light by an acoustic wave, being propagated in a medium of interaction, in 1922.
- In 1932, Debye and Sears, Lucas and Biquard carried out the first experiments to check the phenomenon.
- The particular case of diffraction on the first order, under a certain angle of incidence, (also predicted by Brillouin), has been observed by Rytow in 1935.
- Raman and Nath (1937) have designed a general ideal model of interaction taking into account several orders. This model was developed by Phariseau (1956) for diffraction including only one diffraction order.
- Zenith developed acousto-optic devices for experimental color television using filtered white light sources.
- The invention of the laser led the development of acousto-optics and its applications, mainly for beam deflection, modulation and signal processing. Technical progresses in both crystal growth and high frequency piezoelectric transducers have brought valuable benefits to acousto-optic components' improvements.
[edit] Materials
Some materials displaying acousto-optic effect include fused silica, arsenic trisulfide, tellurium dioxide and tellurite glasses, lead silicate, Ge55As12S33, mercury(I) chloride, lead(II) bromide, and other materials.
