US3828276A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High efficiency acousto-optical q-switch
Assignee: Excel Technology Inc
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Filing: 1973-05-25
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Granted: 1974-08-06
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Expires: 1993-05-25
Abstract
Abstract In a solid state, Q-switched laser oscillator of the type in which the laser medium emits unpolarized light and the acoustooptical Q-switch exhibits strong optical polarization dependence, a first quarter-wave plate disposed within the optical cavity between the Q-switch and one cavity mirror for causing the polarization components of the light beam resolved along the fast and slow axes of the quarter-wave plate to rotate 90* between successive passages through the Q-switch so that the light which was less strongly scattered during one passage through the Qswitch is more strongly scattered during the next passage through the Q-switch, and a second quarter-wave plate disposed within the optical cavity on the other side of the Q-switch for nullifying the effect of the first quarter-wave plate when the Q-switch is turned off so as to leave the polarization components of the laser oscillation unperturbed. This invention relates to laser Q-switches, and, more particularly, to acousto-optical Q-switches for solid state laser media of the type which inherently produce unpolarized light.
Inventors
- 👤 M Cohen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:23
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; H01S3/11; H01S3/1123; H01S3/117; G; G02; G02F; G02F1/00; G02F1/01; G02F1/11
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
231 words
An acousto-optical Q-switch for use in a laser oscillator including a laser medium for emitting an unpolarized or multiply polarized light beam, a high-reflectivity mirror, and a transmission mirror disposed so as to form a resonant cavity for said light beam, said acousto-optical Q-switch comprising: a body of photoelastic material disposed in said resonant cavity between said high-reflectivity mirror and said laser medium, said body of photoelastic material being optically isotropic and transparent to the wavelength of said light beam; means for intermittently generating a beam of ultrasonic waves in said body of photoelastic material so as to cause Braggeffect scattering of said light beam, the strength of said Bragg-effect scattering being dependent upon the direction of polarization of said light beam in relation to the direction of propagation of said beam of ultrasonic waves; a first quarter-wave plate disposed between said body of photoelastic material and said high-reflectivity mirror, said quarter-wave plate having fast and slow axes oriented at 45* angles to the direction of propagation of said beam of ultrasonic waves whereby the polarization of the light beam emerging from said block of photoelastic material is rotated 90* before reentering said block of photoelastic material so that light of the polarization that was less strongly scattered during one passage through said block of photoelastic material is more strongly scattered on the return passage through said block of photoelastic material.
Claim 2
Dependent Claim
231 words
An acousto-optical Q-switch for use in a laser oscillator including a laser medium for emitting an unpolarized or multiply polarized light beam, a high-reflectivity mirror, and a transmission mirror disposed so as to form a resonant cavity for said light beam, said acousto-optical Q-switch comprising: a body of photoelastic material disposed in said resonant cavity between said high-reflectivity mirror and said laser medium, said body of photoelastic material being optically isotropic and transparent to the wavelength of said light beam; means for intermittently generating a beam of ultrasonic waves in said body of photoelastic material so as to cause Braggeffect scattering of said light beam, the strength of said Bragg-effect scattering being dependent upon the direction of polarization of said light beam in relation to the direction of propagation of said beam of ultrasonic waves; a first quarter-wave plate disposed between said body of photoelastic material and said high-reflectivity mirror, said quarter-wave plate having fast and slow axes oriented at 45* angles to the direction of propagation of said beam of ultrasonic waves whereby the polarization of the light beam emerging from said block of photoelastic material is rotated 90* before reentering said block of photoelastic material so that light of the polarization that was less strongly scattered during one passage through said block of photoelastic material is more strongly scattered on the return passage through said block of photoelastic material.
Claim 3
Dependent Claim
65 words
The acousto-optical Q-switch of claim 1 further comprising: a second quarter-wave plate disposed between said block of photoelastic material and said laser medium, said second quarter-wave plate having its fast and slow axes aligned with the slow and fast axes respectively of said first quarter-wave plate whereby the effect of said first quarter-wave plate is nullified when said beam of ultrasonic waves is turned off.
Claim 4
Dependent Claim
17 words
The acousto-optical Q-switch of claim 2 wherein said body of photoelastic material is made of fused quartz.
Claim 5
Dependent Claim
18 words
The acousto-optical Q-switch of claim 2 wherein said first and second quarter-wave plates are made of crystalline quartz.
Claim 6
Dependent Claim
22 words
The acousto-optical Q-switch of claim 2 wherein said first and second quarter-wave plates are optically contacted to said body of photoelastic material.
Claim 7
Dependent Claim
24 words
The acousto-optical Q-switch of claim 5 wherein the peripheries of said first and second quarter-wave plates are cemented to said body of photoelastic material.
Claim 8
Dependent Claim
16 words
The acousto-optical Q-switch of claim 1 wherein said laser medium is a solid state laser medium.
Claim 9
Dependent Claim
17 words
The acousto-optical Q-switch of claim 7 wherein said solid state laser medium is Neodynium-doped Yttrium Aluminum Garnet.
References Cited (Backward Citations)
US3297876A
Cited
US3613024A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-05 | 1978-02-04 | 1978-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-05 | 1982-02-04 | 1982-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-05 | 1986-02-04 | 1986-08-06 | $7700.00 | Window Closed / Lapsed |