Collective behavior of silver plasma during pulsed laser ablation

Abstract

The present work reports an electrical investigation of silver plasma using a self-fabricated Langmuir probe in air and under a low vacuum (~10 -3 torr). A silver target was irradiated with a Q-switched Nd:YAG laser with the wavelength 1.064 µm, energy 10 mJ, pulse duration 9-14 ns and power 1.1 MW. The collective behavior of a silver plasma plume is studied using a Langmuir probe as an electrical diagnostic technique. By applying different positive and negative voltages to the probe, the respective signals are collected on a four channels digital storage oscilloscope having a frequency of 500 MHz. An I-V curve helps to measure electron temperature and electron density directly and plasma frequency, response time, Debye length and number of particles in 'Debye's sphere' indirectly using the theory of Langmuir probe and mathematical formulas. The floating potential is measured as negative for laser induced silver plasma in air and vacuum, following the theory of plasma.

Investigation of Nd:YAG laser produced tin droplet plasma expansion

“…The similar electrical diagnostic has been employed to study the collective behavior of laser produce silver plasma in Dildar et al's report [8]. In addition, Giovannini et al measured the spatial distribution of the separate ion charge states (Sn + and Sn 2+ ) by an electrostatic energy analyzer [9].…”