Laser-based technological approaches and methods suitable for volumetric optical recording of digitalinformation and creation of images by formation of different kinds of micromarks in the bulk of materials, transparent for a selected laser wavelength, are evaluated and discussed. Along with the analysis of formation of laser-induced parameterized centers with different geometries in glass, some emphasis is put on laser-induced creation of dark marks in organic materials, particularly in polystyrene containing light-absorbing inclusions.
Parameterized marks with varying appearance or data pixels can serve as multi-bit information carriers. The dominant mechanisms of laser radiation absorption and induced formation of marks in different transparent materials are discussed.