Influence of micro and nanostructures on emission properties of nanosecond laser produced plasma

Emission characteristics of nanosecond laser produced plasma (LPP) from structured and pristine silicon (Si) targets were investigated to ascertain laser-target energy coupling and its impact on the number of effective laser pulses that generate structures. Two-dimensional Fast Fourier Transform (2D-FFT) analysis of scanning electron microscopy (SEM) images quantified the surface structural features of the targets. Emissions from neutrals and ions generated from structured targets were approximately three times higher than those from pristine targets, significantly influenced by the micro and nano structures formed at varying numbers of effective pulses, corresponding to different beam scanning velocities. The most intense emissions were observed for the target with highly ordered laser-induced periodic surface structures (LIPSS), thereby enhancing the laser-target coupling efficiency.