Laser beam alteration of workpiece optical properties - e.g. for symbol, character or image production on or within glass workpiece.

: Lenk, A.

Abstract
A method of altering the optical properties of a workpiece surface and/or interior involves energy supply onto and/or into a laser-transparent workpiece using a focussed laser beam having a pulse length of less than 100 ps and a power density of greater than 1010 W/cm2, a vacuum being used when the optical properties of the workpiece surface are to be altered. Preferably, a mode-synchronised Q-switched solid state laser is used. USE - E.g. for producing symbols, characters or images within a glass workpiece. ADVANTAGE - The method avoids surface damage of the workpiece and permits optical property alteration at relatively large depth within a workpiece.