Controlled multi-beam supercontinuum generation in fused silica by means of spatial light modulators

We report on deterministic femtosecond multi-filamentation in fused silica by encoding a diffractive microlens array into a spatial light modulator. The efficiency and focal length of each microlens are electronically controlled. Even for an input inhomogeneous irradiance distribution, this allows for a precise control of the energy coupled to the filaments and the spectra of the generated supercontinuum beams. This method may be useful in different applications such as filamentation-based tumor treatment, laser processing, or spectroscopy.