Measurement of Electron Density from Stark-Broadened Spectral Lines Appearing in Silver Nanomaterial Plasma

Abstract

This work communicates results from optical emission spectroscopy following laser-induced optical breakdown at or near nanomaterial. Selected atomic lines of silver are evaluated for a consistent determination of electron density. Comparisons are presented with Balmer series hydrogen results. Measurements free of self-absorption effects are of particular interest. For several silver lines, asymmetries are observed in the recorded line profiles. Electron densities of interest range from 0.5 to 3 × 10 17 cm −3 for five nanosecond Q-switched Nd:YAG radiation at wavelengths of 1064 nm, 532 nm, and 355 nm and for selected silver emission lines including 328.06 nm, 338.28 nm, 768.7 nm, and 827.3 nm and the hydrogen alpha Balmer series line at 656.3 nm. Line asymmetries are presented for the 328.06-nm and 338.28-nm Ag I lines that are measured following generation of the plasma due to multiple photon absorption. This work explores electron density variations for different irradiance levels and reports spectral line asymmetry of resonance lines for different laser fluence levels.

Imaging spectroscopy of Ag plasmas produced by infrared nanosecond laser ablation

“…The reduction of temperature with time is primarily due to three-body recombination between electrons and ions in the plasma. The values measured were well within the range of LPP temperatures and comparable to other related works published elsewhere 2,15,29,34. In addition, the simulated Saha-LTE spectrum provides relative ion concentrations of different plasma species.…”

Gold Nanoparticle-Enhanced Laser-Induced Breakdown Spectroscopy and Three-Dimensional Contour Imaging of an Aluminum Alloy

“…The electron density has been determined by the Stark broadening. 29,39,40 However, other broadenings are not neglected in measuring the electron density.…”

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

“…They proposed the possible reason as recombination from the higher ionic states. In some earlier studies, 8,16 strong spectral asymmetry was reported for the neutral emission. The observed asymmetry was attributed to the presence of a large micro-electric field in the laser produced plasma depending on the time and spatial location within the plasma plume.…”