Scanning radial laser processing with bi-conical reflection

An apparatus for radial laser processing of a workpiece located on a center axis, comprising:

• a laser beam scanner for directing a laser beam along but offset from the center axis;
• and a bi-conical reflector system including:
• a first conical mirror surface arranged to receive the laser beam from the laser beam scanner, wherein the first conical mirror surface surrounds the center axis, is non-cylindrical and rotationally symmetric about the center axis, and faces away from the center axis to reflect the laser beam radially outwards therefrom, and
• a second conical mirror surface arranged to receive the laser beam from the first conical mirror surface, wherein the second conical mirror surface surrounds the center axis, is rotationally symmetric about the center axis, and faces the center axis so as to reflect the laser beam radially inwards toward the center axis;
• wherein:
• the laser beam scanner is configured to azimuthally, with respect to the center axis, scan a location of incidence of the laser beam on the first conical mirror surface to scan an azimuthal angle of propagation of the laser beam from the second conical mirror surface toward the center axis,
• an axial component, parallel to the center axis, of an initial propagation direction of the laser beam from the laser beam scanner toward the bi-conical reflector system is in a first axial direction, and
• the first and second conical mirror surfaces are at first and second angles to a plane orthogonal to the center axis, each of the first and second angles opening in a direction that is radially inward and axially opposite the first axial direction, the first angle being acute, the second angle being greater than twice the first angle and less than the first angle plus 90 degrees.