US3777280A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser generator of te wave guide modes
Assignee: International Business Machines Corp
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Filing: 1972-07-21
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Granted: 1973-12-04
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Expires: 1992-07-21
Abstract
Abstract Propagating radiation with rotationally symmetric optical modes of the TE01 (and TM01) type show promising properties for future applications. For their generation, laser cavities inherently enhance the rotationally symmetric TEM*01 (and TEM*10) laser modes. These cavities must suppress the otherwise usual fundamental TEM00 mode, and in addition discriminate against unwanted same order modes like the linearly polarized TEM01 and TEM10 laser modes. A birefringent crystal zero degree calcite inserted into the cavity applies higher losses at the aperture to the extraordinary beam showing the TEM*10 mode. Thus, the ordinary beam showing the wanted TEM*01 laser mode is favored. Mode selection is further assisted by a Galilean telescope-like setup of the crystal. Discrimination against fundamental mode and higher order modes may be improved by the insertion of circular or ring shaped apertures in the telescope arrangement.
Inventors
- 👤 D Pohl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:47
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/05; H01S3/08; H01S3/08018; H01S3/0804; H01S3/08045; H01S3/10; H01S3/11; H01S3/1123; H01S3/113; H01S2301/00; H01S2301/20; H01S3/0805; H01S3/08054
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
80 words
A laser having an optical cavity and an active medium for the generation of light in totally rotational symmetric modes having rotationally symmetric polarization as well as intensity polarization, especially the TE01 propagation mode, characterized in that within the optical cavity of said laser, having terminating reflectors, there are provided transverse mode selection means including, for the discrimination between degenerate higher order modes, at least one birefringent uniaxial crystal whose optical axis coincides with the optical axis of the cavity.
Claim 2
Dependent Claim
80 words
A laser having an optical cavity and an active medium for the generation of light in totally rotational symmetric modes having rotationally symmetric polarization as well as intensity polarization, especially the TE01 propagation mode, characterized in that within the optical cavity of said laser, having terminating reflectors, there are provided transverse mode selection means including, for the discrimination between degenerate higher order modes, at least one birefringent uniaxial crystal whose optical axis coincides with the optical axis of the cavity.
Claim 3
Dependent Claim
13 words
The laser of claim 1 wherein said birefringent crystal consists of calcite (CaCO3).
Claim 4
Dependent Claim
21 words
The laser of claim 2 characterized in that said birefringent crystal has the shape of a cylinder with plane front faces.
Claim 5
Dependent Claim
20 words
The laser of claim 3 including optical means for causing the laser beam to be divergent within the birefringent crystal.
Claim 6
Dependent Claim
46 words
The laser of claim 3 characterized in that the birefringent crystal is arranged in a telesCopic lens system between a diverging and a converging lens of the kind of a Galilean telescope, the axis of said telescopic lens system coinciding with the axis of said laser.
Claim 7
Dependent Claim
15 words
The laser of claim 5 characterized in that the telescopic lens system has coincident foci.
Claim 8
Dependent Claim
21 words
The laser of claim 5 characterized in that both foci of the telescopic lens system are separated by a small distance.
Claim 9
Dependent Claim
57 words
The laser of claim 3 characterized in that the birefringent crystal is arranged in a telescopic lens system between converging lenses of the kind of an astronomic telescope, wherein one end of said telescopic lens system has a large laser beam diameter side and the other end of said telescopic system has a small beam diameter side.
Claim 10
Dependent Claim
36 words
The laser of claim 8 characterized in that for the transverse higher mode suppression of the laser light by aperture losses, a circular aperture is arranged between the birefringent crystal and one of said terminating reflectors.
Claim 11
Dependent Claim
29 words
The laser of claim 8 characterized in that a central circular screen is provided at the optical axis to eliminate the ground mode of propagation of the laser light.
Claim 12
Dependent Claim
18 words
The laser of claim 10 characterized in that there is provided a ring-shaped diaphragm for the mode selection.
Claim 13
Dependent Claim
29 words
The laser of claim 8 characterized in that the active medium of the laser is arranged in the cavity before the birefringent crystal at the smaller beam diameter side.
Claim 14
Dependent Claim
29 words
The laser of claim 8 characterized in that the active medium of the laser is arranged in the cavity after the birefringent crystal at the larger beam diameter side.
Claim 15
Dependent Claim
19 words
The laser of claim 1 characterized in that the active medium of the laser is a solid state body.
Claim 16
Dependent Claim
15 words
The laser of claim 1 characterized in that the active medium is a ruby crystal.
Claim 17
Dependent Claim
24 words
The laser of claim 1 characterized in that the active medium of the laser is a glass doped with ions of a transition metal.
Claim 18
Dependent Claim
22 words
The laser of claim 1 characterized in that the active medium of the laser is a gas or a mixture of gases.
Claim 19
Dependent Claim
15 words
The laser of claim 1 characterized in that the laser is a continuous wave laser.
Claim 20
Dependent Claim
16 words
The laser of claim 1 characterized in that the laser is a Q-switched giant pulse laser.
References Cited (Backward Citations)
US3435371A
Cited
US3628173A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-03 | 1977-06-04 | 1977-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-03 | 1981-06-04 | 1981-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-03 | 1985-06-04 | 1985-12-04 | $7700.00 | Window Closed / Lapsed |