Ultrashort pulse laser materials processing

Ultrashort laser pulses have shown a huge potential for precise microstructuring. Apart from processing metallic samples [1], especially the possibility to realize three-dimensionally localized modifications within the bulk of transparent materials has gained significant interest. When intense ultrashort pulses are tightly focused into the transparent material, the intensity in the focal volume can become high enough to initiate nonlinear absorption processes [2]. This localized energy deposition results in permanent structural changes inside the sample without affecting the surface. Depending on the processing parameters, either isotropic refractive index changes, self-organized sub-wavelength structures leading to form birefringence or microvoids can be generated in the focus [3, 4]. In this presentation, the fundamentals of femtosecond volume structuring will be reviewed and different applications will be highlighted.