CA1089066A - Shifting of co.sub.2 laser radiation using rotational raman resonances in h.sub.2 and d.sub.2 - Google Patents
Shifting of co.sub.2 laser radiation using rotational raman resonances in h.sub.2 and d.sub.2Info
- Publication number
- CA1089066A CA1089066A CA302,478A CA302478A CA1089066A CA 1089066 A CA1089066 A CA 1089066A CA 302478 A CA302478 A CA 302478A CA 1089066 A CA1089066 A CA 1089066A
- Authority
- CA
- Canada
- Prior art keywords
- laser
- capillary
- infrared radiation
- diatomic
- molecule comprises
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/30—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
- H01S3/305—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects in a gas
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A device for shifting the frequency of infrared radiation from a CO2 laser by stimulated Raman scattering in either H2 or D2. The device of the preferred embodiment comprises an H2 Raman laser having dichroic mirrors which are reflective for 16 µm radiation and transmittive for 10 µm, disposed at opposite ends of an interaction cell. The interaction cell contains a diatomic molecular gas, e.g., either H2 or D2, and a capillary waveguide disposed within the cell. A liquid nitrogen jacket is provided around the capillary waveguide for the purpose of cooling. In another embodiment the input CO2 radiation is circularly polar-ized using a Fresnel rhomb .lambda./4 plate and applied to an inter-action cell of much longer length for single pass operation.
A device for shifting the frequency of infrared radiation from a CO2 laser by stimulated Raman scattering in either H2 or D2. The device of the preferred embodiment comprises an H2 Raman laser having dichroic mirrors which are reflective for 16 µm radiation and transmittive for 10 µm, disposed at opposite ends of an interaction cell. The interaction cell contains a diatomic molecular gas, e.g., either H2 or D2, and a capillary waveguide disposed within the cell. A liquid nitrogen jacket is provided around the capillary waveguide for the purpose of cooling. In another embodiment the input CO2 radiation is circularly polar-ized using a Fresnel rhomb .lambda./4 plate and applied to an inter-action cell of much longer length for single pass operation.
Description
:a~8~6~
SHI~TING 0~ C02 LASER RADIATIOM USIN~
ROTATIONAL RA~AN RESONANCES IN H2 AND D2 Back~round of ~he Inven~ion The present invention pertains generally to infrared lasers and more particularly to stimulated Raman scattering utilizing rotational transitions in a diatomic molecular gas.
Various methods have been disclosed for shifting fre-quencies of conventional laser outputs in the IR spectrum.
These methods have included four-wave mixing as disclosed in U.S. Patent 4,095,121 issued June 13, 1978 to Richard ~. Begley e~ al. en~itled "Resonantly Enhanced Four-Wave Mixing," and Raman scattering as disclosed in U.S. Patent 4,061,921 issued December 6, 1977 to C. D. Cantrell et al. entitled "Infrared Laser System," of which the present invention comprises an ;~
improvement.
In each of these systems and other previous systems for IR
frequency shifting to a broad range of frequencies, simplicity -and overall efficiency are important factors for economic utilization of the device. By minimizing the steps required for frequency shifting, such as the elimination of the Raman spin flip laser as set forth in the above disclosed U. S.
Patent 4,061,921, the device can be simplified to reduce problems lnherent in more complex systems.
Since the stimulated Raman effect can be produced in a single step with high conversion efficiencies, Raman shifting of a C02 laser output provides high overall efficiencies be-cause of the high efficiencies and well developed technology f C2 lasers. ~owever, Raman gain in gaseous media such as ~-~
H2 or D2 in the infrared required threshold powers for stimu-lated Raman scattering which are near the breakdown threshold ~ ~
of the diatomic molecular gas for single pass focused geometry, ~ -such as suggested by Robert L. Byer, in an article entitled "A
16 ~m Source for Laser Isotope Enrichment" published in IEEE
i~ ,. .. . .
,' ' ' ..
J. of Quantum Electronics, Yol. QE 12-732-733,,November 1976.
Summary of the Invention The present invention overcomes the disadvantages and limi-tations of the prior art by providing an improved device for shifting infrared radiation using rotational Raman resonances in a diatomic molecular gas. The invention utilizes a capillary waveguide in combination with a resonator to considerably reduce threshold intensities required by single pass focused geometry.
The capillary waveguide also allows use of short focal length lenses ~or providing maximum intensity without causing damage ;, to the dichroic mirrors or interaction cell windows. Since the rasona~or allows lower gain parameters due to multiple oscilla- ~ ' tions in the lasing cavity, the size of the device is reduced ,~
substantially and operation is assured within the limitations '' of the breakdown threshold of the gaseous medium. Further, ~, . - .
the invention employs circular polarization to increase Raman gain and restrahl reflectivity to reduce waveguide losses. '~ ' The present invention accordingly comprises, a Raman laser for frequency shifting infrared radiation from an infrared radiation source comprising: an interaction cell containing a diatomic molecular gas; a capillary waveguide disposed within the interaction cell; dichroic means disposed at each end of the inter-action cell for primarily reflecting frequency shifted radiation , and primarily transmLtting the infrared radiation from the infrarad radiation source; whereby the capillary waveguide in-creases focal interaction length between the infrared radiation ' from said infrared radiation source and the diatomic molecular gas to overcome losses and produce stimulated Raman scattered requency shifted radiation from rotational transitions in the diatomic molecular gas.
:~, It is there~ore an object of the present invention to pro-vide a device for shi.ftin~ across a b.road ran~e of frequencies in the infrared spectrumO
It is also an object of the present invention to provide a device for shifting across a broad range of IR frequencies which is simple in operation.
Another object of the present invention is to provide a device for IR frequency shifting across a broad range of ~re-quencies which is highly efficient in operation. ~ :
Another object of the present invention is to provide a .~ -device for stimulated Raman scattering in a diatomic molecular .
gas. .
Other objects and fùrther scope of applicability of the present invention will become apparent from the detailed .~' ,.
.. . .
':'.',~, :, :, .
" .
.'.'. . ,'.
' '', ' ,, ,. i . .
- 3a - :.
. .
' 6~
description ~iven hereinafter, Detailed description indicating the preferred embodi~ent o~ the invention is ~iven only by way of illustration since various changes and modifications within the spirit and scope o~ -the invention will become apparent to those skilled in the art from this detailed description. The foregoing abstract of the disclosure is for the purpose o-f pro-viding a non-legal brief statement to serve as a searching and scanning tool for scientists~ engineers and researchers and it is not intended to limit the scope of the invention as disclosed herein nor is it intended to be used in interpreting vr any way limiting the scope or fair meaning of the appended claims.
Brief Description of the Drawings ~ -Figure 1 discloses the Raman laser of the preferred embodi-ment of the invention~
Figure 2 discloses a variation of the preEerred embodiment of Figure 1, Figure 3 discloses an alternative embodiment.
Detailed Description o~ the Preferred Embodiment of the Invention ~ ;
Figure 1 discloses the Raman laser which comprises the pre-ferred em~odiment o the invention~ C02 input radiation 10 isapplied to spatial filter 12 to eliminats "hot spots'l from the spatial intensity of the beam which prevents possible damage to various mirrors and windows of the Raman oscillator, The spa-tially filtered beàm is reflected by mirror 14 and focused by lens 16 through dichroic mirror 18 into the interaction cell 20~ -~Dichroic mirrors 18 and 30 function to transmit the 10 ~m in-frared radiation produced by the CO2 radiation source and re~ ' flect nearly all of the frequenc~ shifted radiation ~enerated within th~ interaction cell 20 produced ~y stimulated Ramanscattering from rotational transitions o~ a diatomic molecul~r .
6 ~
~as such as H2 or D2~ ~ capill~ry waveguide 22 is po~itioned within the interaction ceIl 2Q SUch that the di~tomic molecular gas flowing through the interaction cell 20 via gas inlet 26 and gas outlet 28 is contained ~lthin the capillary waveguide 22, A liquid nitrogen jacket 24 surrounds the primary length of the capillary waveguide 22 and functions to cryogenically cool the diatomic molecular gas to maintain ground state popu-lation. The capillary waveguide 22 is tapered at one end to minimize ablation or sputtering of the waveguide ma~erial upon the application of infrared radiation from the infrared CO2 radiation source, The capillary 22 can be constructed of pyrex or quartz or of either MgO or A12O3 to reduce losses as a result of restrahl reflectivity o~ these materials at desired IR fre- ~
quencies. A LiF restrahl filter 32 reflects the frequency ~ ;
shifted radiation which is focused by lens 34 upon a 14 ~m to 17 ~m ~ilter 36. A HgCdTe or other infrared type detector 38 is utilized to detect the presence of desired spectral lines.
In operation, the device o Fig. 1 functions as a Raman oscillator in which the capillary waveguide 22 increases the
SHI~TING 0~ C02 LASER RADIATIOM USIN~
ROTATIONAL RA~AN RESONANCES IN H2 AND D2 Back~round of ~he Inven~ion The present invention pertains generally to infrared lasers and more particularly to stimulated Raman scattering utilizing rotational transitions in a diatomic molecular gas.
Various methods have been disclosed for shifting fre-quencies of conventional laser outputs in the IR spectrum.
These methods have included four-wave mixing as disclosed in U.S. Patent 4,095,121 issued June 13, 1978 to Richard ~. Begley e~ al. en~itled "Resonantly Enhanced Four-Wave Mixing," and Raman scattering as disclosed in U.S. Patent 4,061,921 issued December 6, 1977 to C. D. Cantrell et al. entitled "Infrared Laser System," of which the present invention comprises an ;~
improvement.
In each of these systems and other previous systems for IR
frequency shifting to a broad range of frequencies, simplicity -and overall efficiency are important factors for economic utilization of the device. By minimizing the steps required for frequency shifting, such as the elimination of the Raman spin flip laser as set forth in the above disclosed U. S.
Patent 4,061,921, the device can be simplified to reduce problems lnherent in more complex systems.
Since the stimulated Raman effect can be produced in a single step with high conversion efficiencies, Raman shifting of a C02 laser output provides high overall efficiencies be-cause of the high efficiencies and well developed technology f C2 lasers. ~owever, Raman gain in gaseous media such as ~-~
H2 or D2 in the infrared required threshold powers for stimu-lated Raman scattering which are near the breakdown threshold ~ ~
of the diatomic molecular gas for single pass focused geometry, ~ -such as suggested by Robert L. Byer, in an article entitled "A
16 ~m Source for Laser Isotope Enrichment" published in IEEE
i~ ,. .. . .
,' ' ' ..
J. of Quantum Electronics, Yol. QE 12-732-733,,November 1976.
Summary of the Invention The present invention overcomes the disadvantages and limi-tations of the prior art by providing an improved device for shifting infrared radiation using rotational Raman resonances in a diatomic molecular gas. The invention utilizes a capillary waveguide in combination with a resonator to considerably reduce threshold intensities required by single pass focused geometry.
The capillary waveguide also allows use of short focal length lenses ~or providing maximum intensity without causing damage ;, to the dichroic mirrors or interaction cell windows. Since the rasona~or allows lower gain parameters due to multiple oscilla- ~ ' tions in the lasing cavity, the size of the device is reduced ,~
substantially and operation is assured within the limitations '' of the breakdown threshold of the gaseous medium. Further, ~, . - .
the invention employs circular polarization to increase Raman gain and restrahl reflectivity to reduce waveguide losses. '~ ' The present invention accordingly comprises, a Raman laser for frequency shifting infrared radiation from an infrared radiation source comprising: an interaction cell containing a diatomic molecular gas; a capillary waveguide disposed within the interaction cell; dichroic means disposed at each end of the inter-action cell for primarily reflecting frequency shifted radiation , and primarily transmLtting the infrared radiation from the infrarad radiation source; whereby the capillary waveguide in-creases focal interaction length between the infrared radiation ' from said infrared radiation source and the diatomic molecular gas to overcome losses and produce stimulated Raman scattered requency shifted radiation from rotational transitions in the diatomic molecular gas.
:~, It is there~ore an object of the present invention to pro-vide a device for shi.ftin~ across a b.road ran~e of frequencies in the infrared spectrumO
It is also an object of the present invention to provide a device for shifting across a broad range of IR frequencies which is simple in operation.
Another object of the present invention is to provide a device for IR frequency shifting across a broad range of ~re-quencies which is highly efficient in operation. ~ :
Another object of the present invention is to provide a .~ -device for stimulated Raman scattering in a diatomic molecular .
gas. .
Other objects and fùrther scope of applicability of the present invention will become apparent from the detailed .~' ,.
.. . .
':'.',~, :, :, .
" .
.'.'. . ,'.
' '', ' ,, ,. i . .
- 3a - :.
. .
' 6~
description ~iven hereinafter, Detailed description indicating the preferred embodi~ent o~ the invention is ~iven only by way of illustration since various changes and modifications within the spirit and scope o~ -the invention will become apparent to those skilled in the art from this detailed description. The foregoing abstract of the disclosure is for the purpose o-f pro-viding a non-legal brief statement to serve as a searching and scanning tool for scientists~ engineers and researchers and it is not intended to limit the scope of the invention as disclosed herein nor is it intended to be used in interpreting vr any way limiting the scope or fair meaning of the appended claims.
Brief Description of the Drawings ~ -Figure 1 discloses the Raman laser of the preferred embodi-ment of the invention~
Figure 2 discloses a variation of the preEerred embodiment of Figure 1, Figure 3 discloses an alternative embodiment.
Detailed Description o~ the Preferred Embodiment of the Invention ~ ;
Figure 1 discloses the Raman laser which comprises the pre-ferred em~odiment o the invention~ C02 input radiation 10 isapplied to spatial filter 12 to eliminats "hot spots'l from the spatial intensity of the beam which prevents possible damage to various mirrors and windows of the Raman oscillator, The spa-tially filtered beàm is reflected by mirror 14 and focused by lens 16 through dichroic mirror 18 into the interaction cell 20~ -~Dichroic mirrors 18 and 30 function to transmit the 10 ~m in-frared radiation produced by the CO2 radiation source and re~ ' flect nearly all of the frequenc~ shifted radiation ~enerated within th~ interaction cell 20 produced ~y stimulated Ramanscattering from rotational transitions o~ a diatomic molecul~r .
6 ~
~as such as H2 or D2~ ~ capill~ry waveguide 22 is po~itioned within the interaction ceIl 2Q SUch that the di~tomic molecular gas flowing through the interaction cell 20 via gas inlet 26 and gas outlet 28 is contained ~lthin the capillary waveguide 22, A liquid nitrogen jacket 24 surrounds the primary length of the capillary waveguide 22 and functions to cryogenically cool the diatomic molecular gas to maintain ground state popu-lation. The capillary waveguide 22 is tapered at one end to minimize ablation or sputtering of the waveguide ma~erial upon the application of infrared radiation from the infrared CO2 radiation source, The capillary 22 can be constructed of pyrex or quartz or of either MgO or A12O3 to reduce losses as a result of restrahl reflectivity o~ these materials at desired IR fre- ~
quencies. A LiF restrahl filter 32 reflects the frequency ~ ;
shifted radiation which is focused by lens 34 upon a 14 ~m to 17 ~m ~ilter 36. A HgCdTe or other infrared type detector 38 is utilized to detect the presence of desired spectral lines.
In operation, the device o Fig. 1 functions as a Raman oscillator in which the capillary waveguide 22 increases the
2~ focal interaction length (L) by the length of the capillary 22.
Stimulated Raman scattering is initiated by rotational transi~
tions of the diatomic molecular gas. Frequency shifted radia-tion produced by Raman scattering oscillates within the optical cavity of the Raman laser defined by dichroic mirrors 18 and `~i!`:; '- '' ' 30, and a portion of this energy is emitted from the oscil-lating cavity via partially reflective dichroic mirror 30. The ~ocal interaction length is therefore increased by thP number of times the frequency shifted radiatlon traverses the length of ~he capillary waveguide, This large increase in the focal interaction length (L~ increases the exponential gain factor (egL~ by an amount sufficient to overcome losses and produce a frequency shifted output si~n~l~
Dia~omic molecular gases suitable for ope~ation in such a device comprise both D2 and H2. Stimulated Raman scattering from rotation transitions of H2 give coverage throughout the range 13~5 to 18 ~m using the 354 cm 1 SOO(O) transition and from 2q to 30 ~m using the 587 cm 1 Soo~I) transition~ Rotational ;
transitions of D2 give co~erage from 11 ~m to 14 ~m using the 179 cm l SOO(O) transition, 12~6 ~m to 16 ! 9 ~m using the 298 cm 1 Soo~l) transition, and 14~7 ~m to 21 ~m using ~he 415 cm Soo(2) transition~ With a tunable high pressure CO2 laser utilizing either D2 or H2, any wavelength in the range 11 ~m to 30 ~m can be generated hy Raman lasing in the device of the preferred embodi~lent.
Figure 2 discloses a variation of the preferred embodi-~ent of Fig. 1 in which a Fresnel rhomb ~/4 pla~e 44 is intro-duced between the spatial filter 12 and focusing optics 16.
The Fresnel rhomb ~/4 plate 44 ~unctions to circularly polarize the infrared radia-tion 10 from the inrared CO radiation source.
When circularly polarized radiation is applied to the interaction cell 20:, it increases Raman gain and reduces anti-Stokes genera-tion in the diatomic molecular gas.
Figure 3 discloses an alternative embodiment in which CO2 IR radiation 46 is circularly polarized by Fresnel rhomb ~/4 __ plate 52 and applied to a single pass interaction cell 72, The single pass interaction cell comprises a several meter long cap-illary 64 positioned within the interaction cell 72 which con-tains the desired diatomic molecular gas D2 or ~2~ The capil~
lary is cooled by a liquid nitro~en cooling jacket or trough 68 to maintain ground state population in the diatomic molecula~
gas. ~ flat window 60 is utili~ed rather than a Brewster angle ~indow because of the circular polarization of the IR radiation.
., "' '." .
' ': .
The use of circularly polarized light in the embodiment of Fig. 3 is especially necessary to reduce competition from an-ti-Stokes generation. In the embodiment of Fig~ 3, interaction length i9 provided by extending the length of the capillary 64 rather than by multiple passes in the ~aman oscillator as accomplished in the :~
devices of Figs, 1 and 2.
The present invention therefore provides a means for in- .
creasing the exponential gain factor (egL) sufficiently to over-come losses in the molecular gas and produce stimulated Raman 10 scattered frequency shifted radiation from rotational transl- :~
tions. The embodiments of the present invention have the ad-vantage of simplicity and single step operation for generating a wide range of frequencies in the infrared spectral region~
Obviously many modifications and variations of the present i~vention are possible in light of the above teachings. It is therefore to be understood that within the scope of the ap~ended claims the invention may be practiced otherwise than is described,
Stimulated Raman scattering is initiated by rotational transi~
tions of the diatomic molecular gas. Frequency shifted radia-tion produced by Raman scattering oscillates within the optical cavity of the Raman laser defined by dichroic mirrors 18 and `~i!`:; '- '' ' 30, and a portion of this energy is emitted from the oscil-lating cavity via partially reflective dichroic mirror 30. The ~ocal interaction length is therefore increased by thP number of times the frequency shifted radiatlon traverses the length of ~he capillary waveguide, This large increase in the focal interaction length (L~ increases the exponential gain factor (egL~ by an amount sufficient to overcome losses and produce a frequency shifted output si~n~l~
Dia~omic molecular gases suitable for ope~ation in such a device comprise both D2 and H2. Stimulated Raman scattering from rotation transitions of H2 give coverage throughout the range 13~5 to 18 ~m using the 354 cm 1 SOO(O) transition and from 2q to 30 ~m using the 587 cm 1 Soo~I) transition~ Rotational ;
transitions of D2 give co~erage from 11 ~m to 14 ~m using the 179 cm l SOO(O) transition, 12~6 ~m to 16 ! 9 ~m using the 298 cm 1 Soo~l) transition, and 14~7 ~m to 21 ~m using ~he 415 cm Soo(2) transition~ With a tunable high pressure CO2 laser utilizing either D2 or H2, any wavelength in the range 11 ~m to 30 ~m can be generated hy Raman lasing in the device of the preferred embodi~lent.
Figure 2 discloses a variation of the preferred embodi-~ent of Fig. 1 in which a Fresnel rhomb ~/4 pla~e 44 is intro-duced between the spatial filter 12 and focusing optics 16.
The Fresnel rhomb ~/4 plate 44 ~unctions to circularly polarize the infrared radia-tion 10 from the inrared CO radiation source.
When circularly polarized radiation is applied to the interaction cell 20:, it increases Raman gain and reduces anti-Stokes genera-tion in the diatomic molecular gas.
Figure 3 discloses an alternative embodiment in which CO2 IR radiation 46 is circularly polarized by Fresnel rhomb ~/4 __ plate 52 and applied to a single pass interaction cell 72, The single pass interaction cell comprises a several meter long cap-illary 64 positioned within the interaction cell 72 which con-tains the desired diatomic molecular gas D2 or ~2~ The capil~
lary is cooled by a liquid nitro~en cooling jacket or trough 68 to maintain ground state population in the diatomic molecula~
gas. ~ flat window 60 is utili~ed rather than a Brewster angle ~indow because of the circular polarization of the IR radiation.
., "' '." .
' ': .
The use of circularly polarized light in the embodiment of Fig. 3 is especially necessary to reduce competition from an-ti-Stokes generation. In the embodiment of Fig~ 3, interaction length i9 provided by extending the length of the capillary 64 rather than by multiple passes in the ~aman oscillator as accomplished in the :~
devices of Figs, 1 and 2.
The present invention therefore provides a means for in- .
creasing the exponential gain factor (egL) sufficiently to over-come losses in the molecular gas and produce stimulated Raman 10 scattered frequency shifted radiation from rotational transl- :~
tions. The embodiments of the present invention have the ad-vantage of simplicity and single step operation for generating a wide range of frequencies in the infrared spectral region~
Obviously many modifications and variations of the present i~vention are possible in light of the above teachings. It is therefore to be understood that within the scope of the ap~ended claims the invention may be practiced otherwise than is described,
Claims (20)
1. A Raman laser for frequency shifting infrared radiation from an infrared radiation source comprising:
an interaction cell containing a diatomic molecular gas;
a capillary waveguide disposed within said interaction cell;
dichroic means disposed at each end of said interaction cell for primarily reflecting frequency shifted radiation and primarily transmitting said infrared radiation from said infrared radiation source;
whereby said capillary waveguide increases focal inter-action length between said infrared radiation from said infrared radiation source and said diatomic molecular gas to overcome losses and produce stimulated Raman scattered frequency shifted radiation from rotational transitions in said diatomic molecular gas.
an interaction cell containing a diatomic molecular gas;
a capillary waveguide disposed within said interaction cell;
dichroic means disposed at each end of said interaction cell for primarily reflecting frequency shifted radiation and primarily transmitting said infrared radiation from said infrared radiation source;
whereby said capillary waveguide increases focal inter-action length between said infrared radiation from said infrared radiation source and said diatomic molecular gas to overcome losses and produce stimulated Raman scattered frequency shifted radiation from rotational transitions in said diatomic molecular gas.
2. The laser of claim 1 further comprising:
a spatial filter aligned with said infrared radiation source; and means for focusing said infrared radiation from said infrared radiation source, said means for focusing having a short focal length to maximize radiation intensity with-in said capillary waveguide without causing window damage to said dichroic means.
a spatial filter aligned with said infrared radiation source; and means for focusing said infrared radiation from said infrared radiation source, said means for focusing having a short focal length to maximize radiation intensity with-in said capillary waveguide without causing window damage to said dichroic means.
3. The laser of claim 1 wherein said capillary comprises a MgO capillary having restrahl reflectivity to reduce losses.
4. The laser of claim 1 wherein said capillary comprises an Al2O3 capillary having restrahl reflectivity to reduce losses.
5. The laser of claim 1 wherein said capillary is cryogen-ically cooled to maintain ground state population of said diatomic molecular gas.
6. The laser of claim 1 wherein said infrared radiation source is a variable frequency CO2 laser.
7. The laser of claim 2 wherein said capillary comprises a MgO capillary having restrahl reflectivity to reduce losses.
8. The laser of claim 2 wherein said capillary comprises an Al2O3 capillary having restrahl reflectivity to reduce losses.
9. The laser of claim 2 wherein said capillary is cryogenically cooled to maintain ground state population of said diatomic molecular gas,
10. The laser of claim 2 wherein said infrared radiation source is a variable frequency CO2 laser.
11. The laser of claim 1 wherein said diatomic molecule comprises H2.
12. The laser of claim 1 wherein said diatomic molecule comprises D2.
13. The laser of claim 2 wherein said diatomic molecule comprises H2.
14. The laser of claim 2 wherein said diatomic molecule comprises D2.
15. The laser of claim 3 wherein said diatomic molecule comprises H2.
16. The laser of claim 3 wherein said diatomic molecule comprises D2.
17. The laser of claim 4 wherein said diatomic molecule comprises H2.
18. The laser of claim 4 wherein said diatomic molecule comprises D2.
19. The laser of claim 5 wherein said diatomic molecule com-prises D2.
20. The laser of claim 1 further comprising means for circularly polarizing said infrared radiation to increase Raman gain and reduce anti-Stokes generation within said capillary waveguide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US80240077A | 1977-06-01 | 1977-06-01 | |
| US802,400 | 1977-06-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1089066A true CA1089066A (en) | 1980-11-04 |
Family
ID=25183597
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA302,478A Expired CA1089066A (en) | 1977-06-01 | 1978-05-02 | Shifting of co.sub.2 laser radiation using rotational raman resonances in h.sub.2 and d.sub.2 |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS54994A (en) |
| CA (1) | CA1089066A (en) |
| DE (1) | DE2824087A1 (en) |
| FR (1) | FR2401538A1 (en) |
| GB (1) | GB1587992A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4222011A (en) * | 1978-10-03 | 1980-09-09 | The United States Of America As Represented By The United States Department Of Energy | Stokes injected Raman capillary waveguide amplifier |
| US4697888A (en) * | 1982-04-21 | 1987-10-06 | Chevron Research Company | Frequency shifted cavity for electromagnetic radiation |
| US4586184A (en) * | 1983-10-21 | 1986-04-29 | Chevron Research Company | Acoustically controlled frequency shifted cavity for electromagnetic radiation |
| JPH02260589A (en) * | 1989-03-31 | 1990-10-23 | Power Reactor & Nuclear Fuel Dev Corp | Optical waveguide type infrared raman laser |
| JPH0330868A (en) * | 1989-06-27 | 1991-02-08 | Fuji Xerox Co Ltd | Coating material circulating apparatus for immersion coating |
| CN113916864B (en) * | 2021-10-09 | 2024-04-19 | 中国工程物理研究院激光聚变研究中心 | ICF target D2Method for quantitative analysis of Raman spectrum of fuel gas |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3655993A (en) * | 1970-07-10 | 1972-04-11 | Bell Telephone Labor Inc | Optically rotatory dielectric-guided parametric oscillators |
| US4061921A (en) * | 1974-05-02 | 1977-12-06 | The United States Of America As Represented By The United States Energy Research & Development Administration | Infrared laser system |
-
1978
- 1978-05-02 CA CA302,478A patent/CA1089066A/en not_active Expired
- 1978-05-02 GB GB1727578A patent/GB1587992A/en not_active Expired
- 1978-05-30 FR FR7816131A patent/FR2401538A1/en not_active Withdrawn
- 1978-06-01 DE DE19782824087 patent/DE2824087A1/en not_active Withdrawn
- 1978-06-01 JP JP6628078A patent/JPS54994A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| GB1587992A (en) | 1981-04-15 |
| FR2401538A1 (en) | 1979-03-23 |
| DE2824087A1 (en) | 1978-12-14 |
| JPS54994A (en) | 1979-01-06 |
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