Dynamic holographic velocimeter for the measurement of vibrations
AssigneeCentre National de la Recherche Scientifique (CNRS)
InventorsPhilippe Delaye, Gérald Roosen
Life of this patent
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Abstract
A process for velocimetric measurement of a target including causing interference in a dynamic holographic material of a reference laser beam and a beam diffused by the target, and measuring variations in luminous intensity transmitted by the material with a photoelectric detector, wherein the target vibrates with a displacement greater than the wavelength and with an extension limited around a mean position.
Claims24
A process for velocimetric measurement of a target comprising:
- causing interference in a dynamic holographic material of a reference laser beam and a beam diffused by the target to produce a signal beam having a luminous intensity that varies in relation to the instantaneous velocity of said target, all of said beams having a predetermined wavelength,
- measuring variations in said luminous intensity transmitted by the material with a photoelectric detector, wherein the target vibrates with a displacement greater than said wavelength and limited around a mean position, and
- determining said velocity based upon said luminous velocity.
A velocimeter comprising:
- a laser which produces a beam;
- a beam separator which divides the beam into a reference beam and a target beam;
- a target vibrating at a frequency lower than about 10 kHz with an amplitude greater than about 0.1 μm around a mean position, said target diffusing said target beam;
- a dynamic holographic material into which the reference and target beams are directed creating an interference pattern that produces a signal beam having a luminous intensity that varies in relation to the instantaneous velocity of said target,
- a photodetector which detects said variations in said luminous intensity of said signal beam produced by the dynamic holographic material, and
- an electronic processor for determining said velocity from said variations in said luminous intensity.
A process for velocimetric measurement of a target that is vibrating with a displacement limited around a mean position comprising the steps of:
- causing interference in a dynamic holographic material of a reference laser beam and a beam diffused by said target to produce a signal beam having a luminous intensity that varies in relation to the instantaneous velocity of vibration of said target;
- detecting said variations of said luminous intensity of said signal beam;
- and
- determining said velocity from said variations in luminous intensity.
A velocimeter comprising:
- a laser producing a beam divided into a reference beam and a target beam diffused by a target vibrating at a frequency lower than 10 kHz with a displacement of greater than 0.1 μm around a mean position;
- a dynamic holographic material in which said two beams interfere to produce a signal beam having a luminous intensity that varies in relation to the instantaneous velocity of said target;
- a photodetector for detecting variations in said luminous intensity of said signal beam;
- and
- an electronic processor for determining velocity from said variations in luminous intensity.
Dependencies are inferred from the claim text.