Time-resolved and time-integrated single-shot laser-induced plasma experiments using nanosecond and femtosecond laser pulses

Abstract

A comparison of single-shot laser-induced breakdown spectroscopy (LIBS) measurements is performed using a unique chirped pulse amplification (CPA) laser system. Depending on the injection by a femtosecond Ti/Sa oscillator, two different temporal regimes can be accessed (femtosecond and nanosecond) while keeping the same wavelength and fluence on the sample (≈ 100 J/cm 2). The sample is a nonpolished pure aluminum plate. Time-resolved spectra obtained in both the nanosecond and the femtosecond regimes are analyzed concerning first the well-known continuum emission related to the Bremsstrahlung process and then the atomic and ionic spectral lines of aluminum. The temporal behaviors of the continuum and of the spectral lines depend much more on the laser fluence than on the pulse duration. The changes in the intensity levels of the emission lines are investigated when the laser fluence is divided by two. The signal to noise ratio is weaker in the nanosecond regime than in the femtosecond one. However, time-integrated single-shot LIBS is demonstrated in both the femtosecond and nanosecond regimes.