Patent US3720884A successfully refreshed from Google Patents.
US3720884A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for compression of optical laser pulses
Assignee: Massachusetts Institute of Technology
•
Filing: 1970-03-23
•
Granted: 1973-03-13
•
Expires: 1990-03-23
Abstract
Abstract Short optical radiation pulses (picosecond range) passed through an optical Kerr liquid receive a self-phase-modulation which exhibits a frequency sweep in the region of maximum intensity, the slope in time being proportional to the propagation distance. The phase-modulated pulse from the Kerr cell is directed to a dispersive delay line which delays the higher optical frequencies the least thereby compressing the pulse width. Frequency spreads of the order of 103 cm 1 are obtainable and hence significant compression ratios are possible, giving rise to very short pulses in the range of 10 14 to 10 13 sec.
Inventors
- 👤 P Kelley
- 👤 R Fisher
- 👤 T Gustafson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:30
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/35; G02F1/3511
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
132 words
In a pulsed laser system, means for compressing the pulses of frequency, omega o/2 pi , and width Tp issuing from a laser cavity comprising, a medium of length l through which the pulses of laser radiation propagate, the relaxation time Tau of said medium being shorter than Tp and the maximum change of refractive index of said material delta max due to the intensity of the radiation being greater than c/4 omega ol, where c is the velocity of light, whereby the refractive index of said medium at the laser frequency is substantially dependent on the intensity of the radiation, resulting in a substantial phase perturbation across each pulse, and dispersive delay means through which the pulses having the substantial phase perturbation propagate causing a compression of each of the pulses.
Claim 2
Dependent Claim
132 words
In a pulsed laser system, means for compressing the pulses of frequency, omega o/2 pi , and width Tp issuing from a laser cavity comprising, a medium of length l through which the pulses of laser radiation propagate, the relaxation time Tau of said medium being shorter than Tp and the maximum change of refractive index of said material delta max due to the intensity of the radiation being greater than c/4 omega ol, where c is the velocity of light, whereby the refractive index of said medium at the laser frequency is substantially dependent on the intensity of the radiation, resulting in a substantial phase perturbation across each pulse, and dispersive delay means through which the pulses having the substantial phase perturbation propagate causing a compression of each of the pulses.
Claim 3
Dependent Claim
132 words
In a pulsed laser system, means for compressing the pulses of frequency, omega o/2 pi , and width Tp issuing from a laser cavity comprising, a medium of length l through which the pulses of laser radiation propagate, the relaxation time Tau of said medium being shorter than Tp and the maximum change of refractive index of said material delta max due to the intensity of the radiation being greater than c/4 omega ol, where c is the velocity of light, whereby the refractive index of said medium at the laser frequency is substantially dependent on the intensity of the radiation, resulting in a substantial phase perturbation across each pulse, and dispersive delay means through which the pulses having the substantial phase perturbation propagate causing a compression of each of the pulses.
Claim 4
Dependent Claim
132 words
In a pulsed laser system, means for compressing the pulses of frequency, omega o/2 pi , and width Tp issuing from a laser cavity comprising, a medium of length l through which the pulses of laser radiation propagate, the relaxation time Tau of said medium being shorter than Tp and the maximum change of refractive index of said material delta max due to the intensity of the radiation being greater than c/4 omega ol, where c is the velocity of light, whereby the refractive index of said medium at the laser frequency is substantially dependent on the intensity of the radiation, resulting in a substantial phase perturbation across each pulse, and dispersive delay means through which the pulses having the substantial phase perturbation propagate causing a compression of each of the pulses.
Claim 5
Dependent Claim
32 words
In a pulsed laser system as in claim 1 and in which, the medium exhibits a substantial optical Kerr effect and a very short relaxation time relative to the laser pulse duration.
Claim 6
Dependent Claim
22 words
In a pulsed laser system as in claim 2 and in which, the ratio of Tp to Tau is at least 2:1.
Claim 7
Dependent Claim
105 words
In a pulsed laser system as in claim 2 and in which, laser issuing pulses from the laser cavity in the system are initially unmodulated and nearly monochromatic and the nonlinear Kerr effect causes self-phase-modulation of the pulses so that the time derivative of the phase perturbation across a pulse changes abruptly in sign across the pulse, and the dispersive delay means delays different frequency components of the pulses from the medium differently in correspondence with the change of the time derivative of the phase perturbation across a pulse between the peak of the pulse and the point of maximum slope of the time derivative.
Claim 8
Dependent Claim
14 words
In a pulsed laser system as in claim 1 wherein, the medium is CS2.
Claim 9
Dependent Claim
14 words
In a pulsed laser system as in claim 1 wherein, the medium is Chloroform.
Claim 10
Dependent Claim
14 words
In a pulsed laser system as in claim 1 wherein, the medium is Acetone.
Claim 11
Dependent Claim
14 words
In a pulsed laser system as in claim 1 wherein, the medium is Nitrobenzene.
Claim 12
Dependent Claim
18 words
In a pulsed laser system as in claim 1 wherein, the dispersive delay means is a Fabrey-Perot interferomater.
Claim 13
Dependent Claim
19 words
In a pulsed laser system as in claim 1 wherein, the dispersive delay means is a pair of prisms.
References Cited (Backward Citations)
US3551034A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |