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US 4,792,765 AGranted
Laser resonator with high aspect ratio gain region and azimuthally symmetric Fresnel number
AssigneeUnited Technologies Corporation
InventorsDavid C. Smith, Kurt E. Oughstun
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Abstract
An unstable optical resonator having a gain region that has an elliptic or other non-circular cross section still has the benefits of a total collimated cavity Fresnel number that is azimuthally symmetric by the combination of several cavity regions of azimuthally non-uniform Fresnel number of appropriate size.
Claims4
An unstable optical resonator for amplifying optical radiation having a diverging wavefront comprising:
- a feedback region terminating at a feedback mirror having a feedback mirror surface for reflecting optical radiation in a feedback pass and containing an outcoupling aperture located in an outcoupling plane;
- a gain region containing means for producing an inverted state in a gain medium, said gain region having a non-circular cross section and said diverging wavefront having an azimuthally anisotropic electric field in said gain region;
- and
- a back region terminating in a back mirror having a back mirror surface oriented to reflect optical radiation in an output pass back toward said feedback region;
- in which
- each of said regions has a feedback pass Fresnel number and an output pass Fresnel number;
- characterized in that
- said resonator further includes at least one means for changing the cross section of an optical wavefront incident thereon;
- and
- said regions have dimensions related to one another and to the wavelength of said optical radiation such that a total collimated cavity Fresnel number at said outcoupling aperture is substantially azimuthally symmetric.
7 more elements
Dependencies are inferred from the claim text.