A method provides for producing modifications in or on a transparent workpiece using a laser processing device. The laser processing device has a short pulse or ultrashort pulse laser that emits laser radiation having a wavelength in the transparency range of the workpiece and which has a beam-shaping optical unit for beam shaping for focusing the laser radiation. The transparent workpiece is composed of a material that has a plurality of phases, of which at least two phases have different dielectric constants, of which in turn the one phase is a phase embedded in the form of particles, which phase is substantially surrounded by the other phase, and wherein the product of the volume of the particles specified in cubic nanometers and the ratio of the absolute value of the difference of the two different dielectric constants to the dielectric constant of the surrounding phase is greater than 500.