A device and a method for optical engraving of a diffraction grating on a workpiece

Abstract

A device for engraving a diffraction grating on a workpiece, comprises an optical set-up comprising a laser, a beam forming device, a beam splitting device, and a focusing head. The laser is configured to output a laser beam. The beam forming device is configured to control a diameter of and a light intensity distribution in the laser beam, and output a primary laser beam. The beam splitting device is configured for a splitting of the primary laser beam into a plurality of split beams for the engraving. The focusing head comprises a microscope objective lens (109) configured to focus the respective split beams in respective foci on the workpiece, an auto-focusing system configured to produce a positioning signal for adjusting and maintaining a distance between the microscope objective lens and the workpiece in order to maintain the respective foci of the split beams on the workpiece and output the positioning signal; and a micro-actuator configured to receive the positioning signal and adjust the distance between the microscope objective lens and the workpiece, whereby the auto-focusing system and the micro-actuator are operationally connected in a closed-loop. The device for engraving further comprises a positioning device configured to perform a relative positioning between the workpiece in the respective foci of the split beams, and the optical set-up; and a controller configured to control the positioning device and the laser according to engraving instructions for the diffraction grating.

Dependencies are inferred from the claim text.