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Stimulated Brillouin Scattering (SBS)

For intense beams (e.g. laser light) travelling in a medium such as an optical fiber, the variations in the electric field of the beam itself may produce acoustic vibrations in the medium via electrostriction. The beam may undergo Brillouin scattering from these vibrations, usually in opposite direction to the incoming beam, a phenomenon known as stimulated Brillouin scattering (SBS).

Brillouin scattering can be optically stimulated leading to the greatest intensity of the scattering mechanism and consequently an improved signal-to-noise ratio. Brillouin frequency-based technique is opposed to intensity based techniques such as Raman and is inherently more accurate and more stable in the long term, since intensity-based techniques suffer from a high sensitivity to drifts. For liquids and gases, typical frequency shifts are of the order of 1–10 GHz (wavelength shifts of ~1–10 pm for visible light). Stimulated Brillouin scattering is one effect by which optical phase conjugation can take place.


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