Patent EP0547725A1 successfully refreshed from Google Patents.
US5136597A
Expired / Lapsed
US
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Poynting vector walk-off compensation in type ii phasematching
Assignee: Coherent Inc
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Filing: 1991-03-15
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Granted: 1992-08-04
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Expires: 2011-03-15
Abstract
Abstract An improved geometry is disclosed for enhancing the efficiency of second harmonic conversion in a Type II phasematching material. In this approach, the effects of wave vector double refraction are used to compensate for the effects of Poynting vector walk-off. To achieve this goal, the input fundamental beam 32 is arranged to enter the doubling crystal 30 at an oblique angle of incidence. This angle is selected so that the wave vector double refraction angle is equal to the Poynting vector walk-off. In order to maximize doubling efficiency, the axes of the crystal must be oriented so that the optimum phasematching angle coincides with the propagation axis of the refracted fundamental beam travelling in the crystal. The subject invention is particularly suited for use with a KTP crystal in either intracavity doubling or in an external resonant geometry.
Inventors
- 👤 John L. Nightingale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:17
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; H01S3/106; H01S3/108; H01S3/109; G; G02; G02F; G02F1/00; G02F1/35; G02F1/37; G02F1/353; G02F1/3542
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
141 words
A device for efficient nonlinear interactions associated with a laser beam comprising: a birefringent crystalline material of the type that can produce an angular difference between the Poynting vectors associated with the two polarization states of a beam in the material, said material having an input face; and means for directing the beam into the material at an oblique input angle of incidence with respect to the input face such that refraction effects that occur at the input face produce an angular difference in the wave vectors associated with the two polarization states of the beam, with the input angle being selected such that the angular difference in wave vectors compensates for the angular difference in the Poynting vectors and wherein the crystalline axes of the material are oriented with respect to the input face to substantially satisfy the phasematching requirement.
Claim 2
Independent Claim
141 words
A device for efficient nonlinear interactions associated with a laser beam comprising: a birefringent crystalline material of the type that can produce an angular difference between the Poynting vectors associated with the two polarization states of a beam in the material, said material having an input face; and means for directing the beam into the material at an oblique input angle of incidence with respect to the input face such that refraction effects that occur at the input face produce an angular difference in the wave vectors associated with the two polarization states of the beam, with the input angle being selected such that the angular difference in wave vectors compensates for the angular difference in the Poynting vectors and wherein the crystalline axes of the material are oriented with respect to the input face to substantially satisfy the phasematching requirement.
Claim 3
Dependent Claim
18 words
A device as recited in claim 1 wherein said material is used in a Type II phasematching interaction.
Claim 4
Dependent Claim
13 words
A device as recited in claim 2 wherein said crystalline material is KTP.
Claim 5
Dependent Claim
23 words
A device as recited in claim 3 wherein said beam is a fundamental beam and said material is used for second harmonic generation.
Claim 6
Dependent Claim
27 words
A device as recited in claim 4 wherein the wavelength of the fundamental laser beam is 1064 nm and the oblique incidence angle is approximately seven degrees.
Claim 7
Dependent Claim
72 words
A device as recited in claim 5 wherein the material has three orthogonal crystalline axes defined as x, y, and z, and the optimum phasematching angle of the material is oriented at approximately 23 degrees from the x-axis and 90 degrees from the z-axis and wherein the normal to the input face of the material is located at an angle approximately 27 degrees from the x-axis and 90 degrees from the z-axis.
Claim 8
Dependent Claim
29 words
A device as recited in claim 1 wherein said laser beam includes more than one wavelength of radiation and the material is utilized for sum or difference frequency generation.
Claim 9
Dependent Claim
16 words
A device as recited in claim 1 wherein the material is located within a resonant cavity.
Claim 10
Dependent Claim
16 words
A device as recited in claim 8 wherein said resonant cavity is an external resonant ring.
Claim 11
Dependent Claim
15 words
A device as recited in claim 8 wherein said resonant cavity includes a gain medium.
Claim 12
Dependent Claim
178 words
A laser comprising: a resonant cavity; a gain medium located within the resonant cavity; means for exciting the gain medium to generate a laser beam within the resonant cavity; and a birefringent crystalline material located in the cavity, said material being of the type that can produce an angular difference between the Poynting vectors associated with the two polarization states of the laser beam in the crystal, said material having an input face, and wherein said resonant cavity is arranged so that the laser beam is directed into the material at an oblique input angle of incidence with respect to the input face such that refraction effects that occur at the input face produce an angular difference in the wave vectors associated with the two polarization states of the beam, with the input angle being selected such that the angular difference in wave vectors compensates for the angular difference in the Poynting vectors and wherein the crystalline axes of the material are oriented with respect to the input face to substantially satisfy the phasematching requirement for nonlinear interactions.
Claim 13
Dependent Claim
178 words
A laser comprising: a resonant cavity; a gain medium located within the resonant cavity; means for exciting the gain medium to generate a laser beam within the resonant cavity; and a birefringent crystalline material located in the cavity, said material being of the type that can produce an angular difference between the Poynting vectors associated with the two polarization states of the laser beam in the crystal, said material having an input face, and wherein said resonant cavity is arranged so that the laser beam is directed into the material at an oblique input angle of incidence with respect to the input face such that refraction effects that occur at the input face produce an angular difference in the wave vectors associated with the two polarization states of the beam, with the input angle being selected such that the angular difference in wave vectors compensates for the angular difference in the Poynting vectors and wherein the crystalline axes of the material are oriented with respect to the input face to substantially satisfy the phasematching requirement for nonlinear interactions.
Claim 14
Dependent Claim
18 words
A laser as recited in claim 11 wherein said material is used in a Type II phasematching interaction.
Claim 15
Dependent Claim
28 words
A laser as recited in claim 12 wherein said laser beam is at a fundamental wavelength and the material functions to double the frequency of the fundamental wavelength.
Claim 16
Dependent Claim
13 words
A laser as recited in claim 13 wherein said crystalline material is KTP.
Claim 17
Dependent Claim
27 words
A laser as recited in claim 14 wherein the wavelength of the fundamental laser beam is 1064 nm and the oblique incidence angle is approximately seven degrees.
Claim 18
Dependent Claim
75 words
A laser recited in claim 15 wherein the material has three orthogonal crystalline axes defined as x, y, and z, and the optimum phasematching angle of the material is oriented at approximately 23 degrees from the x-axis in the x-y plane and 90 degrees from the z-axis and wherein the normal to the input face of the material is located at an angle approximately 27 degrees from the x-axis and 90 degrees from the z-axis.
Claim 19
Dependent Claim
29 words
A device as recited in claim 11 wherein said laser beam includes more than one wavelength of radiation and the material is utilized for sum or difference frequency generation.
Claim 20
Independent Claim
118 words
A device for improved transmission of a laser beam through a birefringent crystal comprising: a birefringent crystalline material of the type that can produce an angular difference between the Poynting vectors associated with the two polarization states of the beam, said material having an input face; and means for directing the beam into the material at an oblique input angle of incidence with respect to the input face such that refraction effects that occur at the input face produce an angular difference in the wave vectors associated with the two polarization states of the beam, with the input angle being selected such that the angular difference in wave vectors compensates for the angular difference in the Poynting vectors.
Claim 21
Independent Claim
118 words
A device for improved transmission of a laser beam through a birefringent crystal comprising: a birefringent crystalline material of the type that can produce an angular difference between the Poynting vectors associated with the two polarization states of the beam, said material having an input face; and means for directing the beam into the material at an oblique input angle of incidence with respect to the input face such that refraction effects that occur at the input face produce an angular difference in the wave vectors associated with the two polarization states of the beam, with the input angle being selected such that the angular difference in wave vectors compensates for the angular difference in the Poynting vectors.
Claim 22
Dependent Claim
16 words
A device as recited in claim 18 wherein the material is located within a resonant cavity.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-08-04 | 1996-02-03 | 1996-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-04 | 2000-02-03 | 2000-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-04 | 2004-02-03 | 2004-08-04 | $7700.00 | Window Closed / Lapsed |