Glossary
- Refraction index: for a transparent medium, ratio between the light speed in the air and the light speed in the medium ; for a reflective surface in the air or vacuum, the refraction index is « - 1 »
- Acousto optic effect: diffraction of light in a material in which propagates an acoustic wave generating periodic variations in refractive index
- Wavelength ( of a light wave ): distance between two consecutive identical states of the electric ( or magnetic ) field
- Acoustic frequency: frequency of an acoustic wave
- Critical interaction length ( acousto optic ): for a monochromatic light wave propagating perpendicularly to the acoustic wave, distance covered for running through half of an acoustic wavelength in the transverse plane ( plane perpendicular to the light wave propagation ) because of the diffraction - defines an interaction length far below which an acousto optic material may diffract in Raman Nath regime