Time resolved anisotropic emission from an aluminium laser produced plasma

Abstract

The polarisation anisotropy of the emission from a laser produced aluminium plasma has been studied using time and polarisation resolved spectroscopy at various background pressures of air. A Wollaston prism was used to resolve the emission from the plasma into polarisation components that are parallel and orthogonal to the plasma expansion axis. Spectroscopy reveals that as the background pressure is increased, strongly polarised continuum emission dominates at early stages of the plasma formation. The results are compared and contrasted to similar experiments and discussed in the framework of a recombining plasma. Published by AIP Publishing.

Spatio-temporal dynamics of anisotropic emission from nano-second laser produced aluminium plasma

“…This figure shows that the estimated DOP in the present work for the line emission is higher in comparison to the previously reported value. 2,6 Moreover, it reflects a clear reversal in sign at longer distances from the sample. To the best of our knowledge, this is the first time that such a DOP reversal and its spatial dependence are reported.…”

“…Previously reported 2,3,14 studies on anisotropic emissions were mostly restricted to the temporal evolution for a few transitions. Kim et al 6 studied the spatial variation of anisotropy, however, limited to a much smaller distance and for rather low laser fluence.…”

“…Anisotropy in the emission spectra can be quantified in terms of the degree of polarization (DOP). The DOP for a particular spectral emission can be estimated by using the following relationship 2 where I H and I V are the intensities of H and V polarizations respectively. Fig.…”

“…Polarized emission from laser produced plasma (LPP) has been the subject of investigation for many groups in the past. [1][2][3][4][5][6][7] Anisotropy in the emission spectra of the expanding plasma plume is, naturally, riveting due to its importance in deciphering electron distribution 1 and also extracting information regarding selfgenerated electric 8 and magnetic elds. 3 Moreover, it is an interesting aspect in the development of an extreme ultraviolet (EUV) light source for nano-lithography.…”

Recombination contributions to the anisotropic emission from a laser produced copper plasma

“…In a recent article [8], we explored a systematic study of the time-and polarisation-resolved spectroscopy of laser generated aluminium plasmas in a variety of background conditions. Our conclusion was that the anisotropy is driven by radiative recombination losses at early times in the plasma.…”