US4618783A
Expired / Lapsed
US
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Production of short light pulses by time compression
Assignee: Centre National de la Recherche Scientifique
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Filing: 1984-04-23
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Granted: 1986-10-21
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Expires: 2004-04-23
Abstract
Abstract Mono-pulses of light are generated by time compression of laser energy. A Raman medium is located in a low Q energy storage cavity having low losses for light at a predetermined frequency and energy delivered by a laser is that frequency in the storage cavity. The Raman medium is also located in a Stokes cavity dimensioned for having a high gain at a Stokes frequency. Most of the stored energy at the Stokes frequency is extracted by a single to and fro travel through the Stokes cavity.
Inventors
- 👤 Francois Pradere
- 👤 Robert Frey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:01
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/30
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
92 words
A method for generating mono-pulses of light by time compression of laser energy, comprising: providing a Raman medium in a low Q energy storage cavity having low losses for light at a predetermined frequency; storing energy delivered by a laser at said predetermined frequency in said storage cavity; locating said Raman medium in a Stokes cavity having a high gain at a Stokes frequency; and extracting the stored energy at said Stokes frequency, whereby most of the stored energy is extracted by a single to and fro travel through the Stokes cavity.
Claim 2
Independent Claim
92 words
A method for generating mono-pulses of light by time compression of laser energy, comprising: providing a Raman medium in a low Q energy storage cavity having low losses for light at a predetermined frequency; storing energy delivered by a laser at said predetermined frequency in said storage cavity; locating said Raman medium in a Stokes cavity having a high gain at a Stokes frequency; and extracting the stored energy at said Stokes frequency, whereby most of the stored energy is extracted by a single to and fro travel through the Stokes cavity.
Claim 3
Dependent Claim
42 words
A method according to claim 1, wherein a non-linear medium selected to generate a frequency shift is located in said storage cavity and the laser energy is injected into said non linear medium from a laser located outside of said storage cavity.
Claim 4
Independent Claim
80 words
A device for producing mono-pulses of light of short duration, comprising a laser cavity having an optical path and having a high Q, a Stokes cavity having an optical path and having a low Q, a laser in said laser cavity and a Raman medium located in said laser cavity, said Raman medium being also located in said Stokes cavity, said Raman medium being one which converts energy at a frequency of said laser into energy at a Stokes frequency.
Claim 5
Independent Claim
80 words
A device for producing mono-pulses of light of short duration, comprising a laser cavity having an optical path and having a high Q, a Stokes cavity having an optical path and having a low Q, a laser in said laser cavity and a Raman medium located in said laser cavity, said Raman medium being also located in said Stokes cavity, said Raman medium being one which converts energy at a frequency of said laser into energy at a Stokes frequency.
Claim 6
Dependent Claim
63 words
A device according to claim 3, wherein said Stokes cavity is defined by two mirrors at 90° to the optical path of said Stokes cavity, one of said mirrors being substantially fully reflective at the Stokes frequency while the other of said mirrors has a reflection coefficient in the one per cent range of magnitude and low absorpotion losses at the Stokes frequency.
Claim 7
Dependent Claim
39 words
A device according to claim 4, wherein the light splitting means are mirrors having a reflection coefficient close to 100% at one of the Stokes and laser frequencies and a transmission coefficient close to 100% at the other frequency.
Claim 8
Dependent Claim
40 words
A device according to claim 4, further comprising at least a second Raman medium in a second Stokes cavity having a low Q, the two Stokes cavities having an overlapping zone for energy transfer from one Stokes frequency to another.
Claim 9
Dependent Claim
58 words
A device according to claim 3, wherein a zone common to the laser cavity and Stokes cavity is bounded by light splitting means which are transparent for one of the laser and Stokes frequencies and reflective for the other, whereby the light at laser frequency is directed to the laser and the Stokes and laser cavities are uncoupled.
Claim 10
Independent Claim
106 words
A device for producing mono-pulses of light of short duration, comprising a laser for delivering light at a predetermined frequency; a non linear medium, said non linear medium being one which converts light at said predetermined frequency into light at a different storage frequency and located to receive light from said laser; a storage cavity accommodating said non linear medium and having a high Q at said storage frequency; a Raman medium located both in said storage cavity and in a Stokes cavity having a low Q, said Raman medium being one which converts the energy at the storage frequency into energy at a Stokes frequency.
Claim 11
Independent Claim
106 words
A device for producing mono-pulses of light of short duration, comprising a laser for delivering light at a predetermined frequency; a non linear medium, said non linear medium being one which converts light at said predetermined frequency into light at a different storage frequency and located to receive light from said laser; a storage cavity accommodating said non linear medium and having a high Q at said storage frequency; a Raman medium located both in said storage cavity and in a Stokes cavity having a low Q, said Raman medium being one which converts the energy at the storage frequency into energy at a Stokes frequency.
Claim 12
Dependent Claim
35 words
A device according to claim 8, wherein a light beam from said laser is injected into the storage cavity through a dichroic mirror substantially transparent at the laser frequency and reflective at the storage frequency.
Claim 13
Dependent Claim
23 words
A device according to claim 8, wherein a light beam from said laser is injected into the storage cavity through light dispersive means.
Claim 14
Dependent Claim
37 words
A device according to claim 8, wherein the Raman medium is located in containing means constructed and arranged to subject a beam from said laser to multiple reflections to increase the travel length in said Raman medium.
Claim 15
Dependent Claim
17 words
A device according to claim 8, wherein said non-linear medium is one which effects stimulated Raman scattering.
Claim 16
Dependent Claim
18 words
A device according to claim 8, wherein said non linear medium is one which effects a parametric process.
Claim 17
Dependent Claim
17 words
A device according to claim 8, wherein said non linear medium is one which effects frequency doubling.
Claim 18
Dependent Claim
17 words
A device according to claim 8, wherein said non linear medium is one which effects frequency trebling.
References Cited (Backward Citations)
US4348599A
Cited
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