Effect of input pulse chirp on nonlinear energy deposition and plasma excitation in water

Abstract : We analyze numerically and experimentally the effect of the input pulse chirp on the nonlinear energy transfer from 5 µJ fs-pulses at 800 nm to water. Numerical results are also shown for pulses at 400 nm, where linear losses are minimized, and for different focusing geometries. Input chirp is found to have a big impact on the transmitted energy and on the plasma distribution around focus, thus providing a simple and effective mechanism to tune the electron density and energy deposition. We identify three relevant ways in which plasma features may be tuned.