Plasma-mediated ablation using picosecond UV and IR laser pulses and spectroscopical investigations of the plasma spark

摘要

Abstract: In-vitro ablation experiments of calf brain tissue with ultrashort lasers are reported. Excisions have been performed by the mechanism of plasma-mediated ablation with focused picosecond laser pulses. Results achieved with a 35 ps oscillator/regenerative amplifier Nd:YLF laser at 1053 nm and its second and fourth harmonic at 526 and 263 nm, respectively, are presented. Preliminary experiments with 19 ps laser pulses at wavelengths near 3 $mu@m generated by optical parametric amplification are reported. Here, during the ablation with low photon energies no plasma was induced. Furthermore, the spectrum of laser-induced plasma sparks on the surface of fresh calf brain tissue was recorded. Atomic line widths were measured and used to determine the electron density of the plasma. With energy densities of about 100 J/cm$+2$/ values between 2 $DOT 10$+17$/ and 5 $DOT 10$+18$/ cm$+$MIN@3$/ were found. !11