Application of a mode-locked fiber laser for highly time resolved broadband absorption spectroscopy and laser-assisted breakdown on micro-plasmas

Absorption spectroscopy is known to be a powerful tool to gain spatially and temporally resolved information on excited and reactive species in a plasma discharge. Furthermore, the interaction of the discharge with short intense laser pulses can trigger the ignition and the transition into other transient states of the plasma. In this context laser-assisted ‘pump-probe’ experiments involving simultaneously generated supercontinuum radiation yield highly temporally resolved and spatially well-defined information on the transient phenomena. In this paper we demonstrate the possibility for ‘pump–probe’ experiments by initiating breakdown on a picosecond time scale (‘pump’) with a high-power beam and measuring the broadband absorption with the simultaneously provided supercontinuum (‘probe’). Since both pulses are generated from the same mode-locked master oscillator, they have a strong level of synchronization. (Some figures may appear in colour only in the online journal)