Spécifications techniques

Unlike conventional light sources the laser creates coherent, monochromatic and almost non-divergent light.

For the subsurface engraving a laser beam is expanded and then focussed by an objective down to a diameter of approx. 5-10µm.

At the used wavelengths of 1064nm (infrared), 532nm (green) and 355nm (UV), only a negligible part of the radiation is reflected resp. absorbed by most transparent materials such as glass, plastics, sapphire, etc. So these materials are transparent at the given wavelengths.

A non-focussed laser beam would travel through these materials without any interaction with the material.

If the laser beam gets focussed into the material the following happens:

The intensity (I), i.e. the energy per cross-sectional area increases with decreasing beam diameter.

The relating formula is:

I=E/A

The energy (E) of the beam stays constant, the cross-sectional area (A) decreases. Therefore the intensity (I) increases.

From a certain threshold of the intensity Ith, non-linear optical effects lead to an absorption of the laser radiation in the material. The absorption results in a structural change in the material, which appears white in glass due to scattering of the ambient light.

In polycarbonate, the structural changes appear grey due to a carbonisation at the focus.