Method and installation for acousto-optic imaging
AssigneesCentre National de la Recherche Scientifique (CNRS), Universite Pierre et Marie Curie (Paris VI)
InventorsMichel Gross, Francois Georges Gerard Ramaz, Benoit Claude Forget, Gerald Roosen, Philippe Delaye, Albert-Claude Boccara
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Abstract
This invention concerns an acousto-optic imaging method comprising a step which consists in engraving in a dynamic holographic material a complex index array resulting from the interference of the acousto-optic component of the signal wave and a pump wave of frequency equal to the frequency of the acousto-optic component.
Claims27
An acousto-optic tomographic imaging method for an object comprising steps during which:
- (a) the vibration of a three-dimensional area of the object is generated by applying an acoustic wave exhibiting a certain acoustic frequency to the object,
- (b) an incident wave and a pump wave are generated by:
- generating an initial light wave with a light wave generating device, and
- splitting said initial wave into a first beam and a second beam;
- shifting the frequency of said first beam by a first frequency shift in order to generate the incident wave,
- shifting the frequency of said second beam by a second frequency shift in order to generate the pump wave,
- said second frequency shift being roughly equal to the sum of the first frequency shift and the acoustic frequency;
- (c) an incident light wave is applied to said object and a signal light wave is generated by travelling through the object and interacting with the three-dimensional area of the object, said signal light wave comprising at least one acousto-optic component frequency-shifted by said acoustic wave,
- (d) a light pump wave is generated, coherent with said incident wave at a frequency similar to the frequency of said acousto-optic component,
- (e) a complex index grating is formed in a dynamic holographic material by applying said signal wave and said pump wave to said material, and
- (f) a digital parameter relating to the light intensity in this three-dimensional area is obtained from said complex index grating.
An acousto-optic imaging installation for an object comprising:
- (A) a transducer designed to generate the vibration of an area of the object by applying an acoustic wave having an acoustic frequency to the object,
- (B) a device for generating light waves designed to apply to said object an incident light wave and thus generating a signal light wave comprising at least one acousto-optic component frequency-shifted by said acoustic wave, and also designed to generate a light pump wave, coherent with said incident wave at a frequency similar to the frequency of said acousto-optic component,
- (C) a dynamic holographic material adapted so that a complex index grating is formed by the application to said material of said signal wave and of said pump wave, and
- (D) a detection device designed to obtain a digital parameter relating to the light intensity in this area from said complex index grating.
Dependencies are inferred from the claim text.