In-Volume Modification

By means of highly focused ultrashort pulsed laser radiation in the femtosecond range, Fraunhofer ILT has technologies that can selectively modify transparent materials, such as glass, sapphire and other transparent ceramics. The multiphoton absorption processes required for this are only induced at high intensities so that the material is solely changed in the focus volume. Thanks to beam deflection with accuracies in the nanometer range, any 3D geometrical shape can thus be created layer by layer in the volume of the workpieces.

Depending on the parameter set used, the material properties can be influenced in a point-by-point, line-shaped or layer-like manner, thus making the following applications possible:

• Waveguides
• Analysis or data communication
• Diffraction structures
• Markers, holgrams

The laser-induced material modification changes the density of the material and, thus, the refractive index so that the optical properties are changed. Moreover, the modified material show a different etching behavior compared to the unmodified areas. Using material-dependent etching solutions for the transparent materials, almost any 3D structure can be generated using selected laser etching (SLE) method.