Distributed fiber optic laser ultrasonic system
First Claim
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1. Ultrasonic inspection apparatus comprising:
- a high power pulsed laser;
an elongated optical fiber coupled to the laser to transmit energy from the laser along the fiber, the fiber having a core and cladding, and means, at a location along the fiber remote from the laser, for allowing laser energy to leak through the cladding;
a laser energy-responsive sound generating material at said location for generating acoustic vibrations at said location in response to laser energy leaking through the cladding and transmitting said acoustic vibrations to an object to be inspected; and
detecting means for detecting ultrasonic energy reflected from said object.
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Abstract
An optical fiber coupled to a high power laser carries laser energy to la-activated sound generating materials disposed at intervals along its length. The sound-generating materials are acoustically coupled to an object or objects to be monitored. Acoustic reflections from the objects modulate the periods of Bragg gratings formed in a separate core of the fiber, or in the core of a separate fiber. The modulation of a Bragg grating period is detected as a Doppler shift in an interrogation beam reflected by the grating.
39 Citations
12 Claims
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1. Ultrasonic inspection apparatus comprising:
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a high power pulsed laser; an elongated optical fiber coupled to the laser to transmit energy from the laser along the fiber, the fiber having a core and cladding, and means, at a location along the fiber remote from the laser, for allowing laser energy to leak through the cladding; a laser energy-responsive sound generating material at said location for generating acoustic vibrations at said location in response to laser energy leaking through the cladding and transmitting said acoustic vibrations to an object to be inspected; and detecting means for detecting ultrasonic energy reflected from said object. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Ultrasonic inspection apparatus comprising:
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an elongated optical fiber for conducting energy from a laser along the fiber, the fiber having a core and cladding, and means, at a plurality of locations along the fiber for allowing laser energy to leak through the cladding; a laser energy-responsive sound generating material at each said location for generating acoustic vibrations in response to laser energy leaking through the cladding and transmitting said ultrasonic vibrations to an object to be inspected; and detecting means for detecting ultrasonic energy reflected from each said object. - View Dependent Claims (8, 9, 10)
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11. A method of ultrasonic inspection of plural objects comprising the steps of:
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transmitting a high power laser pulse through an optical fiber extending past said objects in close proximity thereto; causing energy from the laser pulse to activate a sound-producing material at each of a plurality of locations along the fiber; transmitting acoustic energy from the sound producing material a t each said location to one of said objects; and detecting reflections of said acoustic energy from said objects. - View Dependent Claims (12)
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Specification