Apparatus for use in correcting beam anamorphicity by vector diffraction
AssigneeEastman Kodak Company
InventorFrederick F. Geyer
Life of this patent
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Abstract
Certain sources of optical radiation, such as diode lasers, emit an anamorphic beam of radiation that is linearly polarized along the major axis. The present invention provides optical apparatus that corrects for such beam anamorphicity through the use of vector diffraction effects.
Claims21
Apparatus comprising:
- (a) a radiation source for producing an anamorphic output beam of optical radiation that is linearly polarized along its major axis;
- (b) means for collimating said output beam of radiation;
- (c) means for rotating the direction of polarization of said collimated beam of radiation to produce a polarization rotated, collimated beam of radiation;
- and
- (d) an optical lens having a numerical aperture greater than about 0.5 for focusing said polarization rotated, collimated beam of radiation to a spot,
- thereby forming a focused spot of optical radiation that is less anamorphic than the output beam of said radiation source.
Apparatus comprising:
- (a) a diode laser;
- (b) means for collimating the output beam produced by said diode laser;
- (c) means for rotating the direction of polarization of said collimated beam of radiation to produce a polarization rotated, collimated beam of radiation;
- and
- (d) an optical lens having a numerical aperture greater than about 0.5 for focusing said polarization rotated, collimated beam of radiation to a spot,
- thereby forming a focused spot of optical radiation that is less anamorphic than the output beam of said diode laser.
Apparatus for use with a source of optical radiation that produces an anamorphic output beam that is linearly polarized along its major axis, said apparatus comprising:
- (a) a first lens for collimating the output beam from said source of optical radiation to produce an anamorphic beam of collimated radiation that is linearly polarized along its minor axis;
- (b) a half-wave plate disposed in the path of said collimated beam for rotating the plane of polarization by 90.degree. so that said collimated beam of radiation is linearly polarized along its major axis;
- and
- (c) a second lens for forming a focused spot of radiation in an image plane located at the focus of said second lens, said second lens having a numerical aperture greater than or equal to 0.5 so that said focused spot is less anamorphic than the output beam produced by said source of radiation.
Apparatus comprising:
- (a) a first lens;
- (b) a diode laser for producing an anamorphic beam of radiation that is linearly polarized along its major axis, said diode laser beam disposed at the focus of said first lens so that said output beam is collimated by said first lens to produce an anamorphic collimated beam of radiation that is linearly polarized along its minor axis;
- (c) means disposed in the optical path of said collimated beam of radiation for rotating the plane of polarization by about 90.degree. so that said collimated beam of radiation is linearly polarized along its major axis;
- and
- (d) a second lens for focusing the collimated beam of radiation from said polarization rotating means into a focused spot, said second lens having numerical aperture greater than or equal to 0.5, so that said focused spot is less anamorphic than the output beam produced by said diode laser.
A method for reducing the anamorphicity of an anamorphic beam of optical radiation that is linearly polarized along its major axis, said method comprising the steps of:
- collimating said beam of optical radiation;
- rotating the direction of polarization of said collimated beam of radiation to produce a polarization rotated, collimated beam of radiation;
- and
- focusing said polarization rotated, collimated beam of radiation to a spot using an optical lens having a numerical aperture greater than about 0.5.
A method for reducing the anamorphicity of an anamorphic output beam of a diode laser, said method comprising the steps of:
- collimating the output beam of said diode laser;
- rotating the direction of polarization of said collimated beam to produce a polarization rotated, collimated beam;
- and
- focusing said polarization rotated, collimated beam to a spot using an optical lens having a numerical aperture greater than about 0.5.
Dependencies are inferred from the claim text.