Spatiotemporally resolved optical emission spectroscopy and harmonic generation in Cu plasmas.

Abstract

[EN]Laser-induced ablation plasmas of Cu generated by nanosecond 1064 nm pulses have been examined as media for third harmonic generation of a nanosecond driving pulse. A narrow window of ablation fluences where third harmonic generation is optimized has been identified in a region around twice the ablation threshold. A detailed analysis of the features of the Cu plasma across this critical fluence window, through spatially and temporally resolved optical emission spectroscopy, has been used to assess critical plasma parameters such as temperature, electron density, and abundance of Cu species in different ionization stages. This description has been correlated with the conditions for optimum low-order harmonic generation in the Cu plasma.