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US 6,633,384 B1Granted
Method and apparatus for ultrasonic laser testing
AssigneeLockheed Martin Corporation
InventorsThomas E. Drake, Jr., Mark A. Osterkamp
Life of this patent
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Abstract
The present invention for detecting ultrasonic displacements includes a detection laser to generate a first pulsed laser beam to generate the ultrasonic surface displacements on a surface of the target. A second pulsed laser beam to detect the ultrasonic surface displacements on a surface of the target. Collection optics to collect phase modulated light from the first pulsed laser beam either reflected or scattered by the target. An interferometer which processes the phase modulated light and generate at least one output signal. A processor that processes the at least one output signal to obtain data representative of the ultrasonic surface displacements at the target.
Claims14
An optical interferometeric apparatus for measuring incoming de-polarized light comprising:
- a first cavity having a first confocal lens structure;
- a second cavity having a second confocal lens structure;
- a beam splitter for dividing incoming de-polarized light into a first polarized light component and a second polarized light component and for directing said first and second polarized light components into the first and second cavities;
- a first collection optics for collecting light transmitted through the first confocal lens structure wherein said collected light being represented by variable VT1;
- a second collection optics for collecting light reflected back through the first confocal lens structure wherein said collected light being represented by variable VR1;
- a third collection optics for collecting light transmitted through the second confocal lens structure wherein said collected light being represented by variable VT2;
- a fourth collection optics for collecting light reflected back through the first confocal lens structure wherein said collected light being represented by variable VT2;
- a control system for adjusting the first cavity to vary an amount of light transmitted through the first cavity in relationship to an amount of light reflected back through the first cavity;
- and
- a second control system for adjusting the second cavity to vary an amount of light transmitted through the second cavity in relationship to an amount of light reflected back through the second cavity.
7 more elements
An interferometeric apparatus for measuring light, comprising:
- a first cavity having a first confocal lens structure;
- a second cavity having a second confocal lens structure;
- a polarized beam splitting assembly to divide incoming de-polarized light into a first polarized light component and a second polarized light component wherein said polarized beam splitting assembly directing said first and second polarized light components into the first and second cavities;
- a first detector positioned to detect a first amount of light transmitted through the first confocal lens structure wherein said first amount being represented by variable VT1;
- a second detector positioned to detect a second amount of light transmitted through the second confocal lens structure wherein said second amount being represented by variable VT2;
- a third detector positioned to detect a first amount of light reflected back through the first confocal lens structure wherein said first amount being represented by variable VR1;
- a fourth detector positioned to detect a second amount of light reflected back through the second confocal lens structure wherein said second amount being represented by variable VR2;
- a first control system to adjust and tune the first cavity to adjust VR1 relative to VT1;
- a second control system to adjust and tune the second cavity to adjust VR2 relative to VT2.
6 more elements
An interferometeric apparatus for measuring light, comprising:
- a first cavity having a first confocal lens structure;
- a second cavity having a second confocal lens structure providing a means for dividing incoming de-polarized light into a first polarized light component and a second polarized light component and for directing said first and second polarized light components into the first and second cavities providing a plurality of detectors for measuring the amount of light transmitted through the first confocal lens structure relative to the amount of light reflected back through the first confocal lens structure providing a relationship which is expressed by formula (VR1/(VR1+VT1));
- a detector for measuring the amount of light transmitted through the second confocal lens structure relative to the amount of light reflected back through the second confocal lens structure providing a relationship which is expressed by formula (VR2/(VR2+VT2));
- and
- a control system for adjusting the first and second cavities to maintain the following relationship despite a variation in intensity of the incoming de-polarized light:
- V R1 V R1 + V T1 = V R2 V R2 + V T2 = a constant
- wherein the constant is a real number between 0.5 and 1.0.
4 more elements
An interferometeric apparatus comprising:
- a first cavity having a first confocal lens structure;
- a second cavity having a second confocal lens structure;
- a device for dividing incoming de-polarized light into a first polarized light component and a second polarized light component, said device also directing said first and second polarized light components into the first and second cavities;
- a control system to adjust said first and second cavities such that a ratio of light transmitted through each cavity to light reflected back through each cavity remains substantially constant.
1 more element
Dependencies are inferred from the claim text.