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US 5,467,335 AGranted
Beam-shaping optical element and device for converting a beam having a first cross-section into a beam having a second cross-section
AssigneeU.S. Philips Corporation
InventorJosephus J. M. Braat
Life of this patent
Estimating the term…
Abstract
A beam-shaping element for converting a beam having an elliptical cross-section into a beam having a circular cross-section. This element has a cylindrical entrance surface and a toriodal exit surface and can be arranged close to a diode laser so that the risk of wavefront deviations due to defocusing is reduced. The element has a high coupling efficiency.
Claims18
A beam-shaping optical element comprising:
- an element material having an entrance surface, an exit surface located opposite thereto and an optical axis which coincides with the Z axis of a three-axis rectangular XYZ system of coordinates for converting a beam having a first longitudinal ratio between a first angular aperture in the YZ plane of the system of coordinates and a second, smaller angular aperture in the XZ plane into a beam having a second longitudinal ratio between said angular apertures, the second longitudinal ratio being smaller than the first longitudinal ratio, said element realising angular magnifications in said two planes wherein the angular magnifications differ from one another, wherein the entrance surface is centrally provided with a substantially cylindrical portion whose cylindrical axis is parallel to the Y axis and introduces an angular reduction of the order of n.sub.1 /n.sub.2 in the YZ plane and an angular magnification of the order of n.sub.2 /n.sub.1 in the XZ plane, in which n.sub.2 and n.sub.1 are the refractive indices of the element material and a medium surrounding the element, respectively, and wherein the exit surface is a toroidal surface whose radius of curvature in the XZ plane is larger than that in the YZ plane.
A radiation source unit comprising:
- a diode laser having a radiation-emitting surface, said diode laser for supplying a beam having a first elliptical cross-section;
- a beam-shaping element for converting the beam supplied by said diode laser into a converted beam having a cross-section which is less elliptical than that of the diode laser beam;
- and
- means for positioning said diode laser and said beam-shaping element with respect to one another such that the distance between the radiation-emitting surface of said diode laser and the entrance plane of said beam-shaping element is at most several hundred .mu.m,
- wherein said beam-shaping element comprises an element material having an entrance surface, an exit surface located opposite thereto and an optical axis which coincides with the Z axis of a three-axis rectangular XYZ system of coordinates for converting a beam having a first longitudinal ratio between a first angular aperture in the YZ plane of the system of coordinates and a second, smaller angular aperture in the XZ plane into a beam having a second longitudinal ratio between said angular apertures, the second longitudinal ratio being smaller than the first longitudinal ratio, said element realising angular magnifications in said two planes wherein the angular magnifications differ from one another, wherein the entrance surface is centrally provided with a substantially cylindrical portion whose cylindrical axis is parallel to the Y axis and introduces an angular reduction of the order of n.sub.1 /n.sub.2 in the YZ plane and an angular magnification of the order of n.sub.2 /n.sub.1 in the XZ plane, in which n.sub.2 and n.sub.1 are the refractive indices of the element material and a medium surrounding the element, respectively, and wherein the exit surface is a toroidal surface whose radius of curvature in the XZ plane is larger than that in the YZ plane.
2 more elements
A radiation source unit comprising:
- a diode laser having a radiation-emitting surface, said diode laser for supplying a beam having a first elliptical cross-section;
- a beam-shaping element for converting the beam supplied by said diode laser into a converted beam having a cross-section which is less elliptical than that of the diode laser beam, wherein said beam-shaping element comprises an element material having an entrance surface, an exit surface located opposite thereto and an optical axis which coincides with the Z axis of a three-axis rectangular XYZ system of coordinates for converting a beam having a first longitudinal ratio between a first angular aperture in the YZ plane of the system of coordinates and a second, smaller angular aperture in the XZ plane into a beam having a second longitudinal ratio between said angular apertures, the second longitudinal ratio being smaller than the first longitudinal ratio, said element realising angular magnifications in said two planes wherein the angular magnifications differ from one another, wherein the entrance surface is centrally provided with a substantially cylindrical portion whose cylindrical axis is parallel to the Y axis and introduces an angular reduction of the order of n.sub.1 /n.sub.2 in the YZ plane and an angular magnification of the order of n.sub.2 /n.sub.1 in the XZ plane, in which n.sub.2 and n.sub.1 are the refractive indices of the element material and a medium surrounding the element, respectively, and wherein the exit surface is a toroidal surface whose radius of curvature in the XZ plane is larger than that in the YZ plane;
- and
- means for positioning said diode laser and said beam-shaping element with respect to one another at a prescribed distance between the radiation-emitting surface of said diode laser and the entrance plane of said beam-shaping element.
1 more element
Dependencies are inferred from the claim text.