Controlling radiation beam diameters
AssigneeCrosfield Electronics Limited
InventorsJohn E. Aughton, James H. Gray
Life of this patent
Estimating the term…
Abstract
The invention relates to a method and an apparatus for reducing the diameter tolerance of a laser beam. A lens (3) is positioned so that one of the focal planes of the lens (3) is in the region of a limit (5) of the Rayleigh range of the beam (19). The lens (3) forms a second beam waist at a position (6), where a modulator (10) is placed. The beam (21) then passes through beam expansion apparatus (11,12,13) before being collimated by a lens (14). The collimated beam (25) is then focussed to a third beam waist at the recording drum (17), via a lens (18) and mirror (15).
Claims5
A method of reducing the tolerance in the diameter of a beam of coherent radiation comprising the fundamental transverse mode and which defines a Rayleigh range, the method comprising positioning a lens such that the focal plane defined by said lens is in the region of a limit of said Rayleigh range of said beam.
Apparatus for generating a beam of coherent radiation comprising said fundamental transverse mode and which defines a Rayleigh range, said apparatus comprising a radiation beam generator;
- and a lens positioned such that the focal plane defined by said lens is in the region of a limit of said Rayleigh range of said beam.
Dependencies are inferred from the claim text.