| 摘要 |
The device, which is provided for interacting with a light beam, comprises means 12 for creating acoustic waves and a medium 6 for propagating these acoustic waves, this medium being transparent to the light beam. The medium is made of an elastomer which is transparent to the light beam, has a very low elastic modulus and a very low glass-transition temperature. The modulation system uses such a device equipped with control means for the modulation of visible or near-infrared light coming from a monomode or multimode fibre, or entering such a fibre. It also applies to the laser velocimeter system which measures the local velocity of a microparticle-entraining fluid by analysing the light scattered by these microparticles when they pass into a zone where the 0-order and 1st-order beams defracted by the device interfere. <IMAGE>
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