A method and device for producing subsurface markings in a transparent
material body by focusing a pulsed laser beam in the interior of the
material body so that the laser beam exceeds the destruction threshold of
the material body to produce a permanent marking. Individual markings
form a freely selectable internal engraving as a result of a relative
movement between the laser beam and the material body. The laser pulse is
varied with respect to its pulse energy (P) by means of a discharge pulse
(E) that has an adjustable time delay from an excitation pulse (A).
Markings that have varying optical properties depending on the pulse
energy (P) are produced in this fashion.