Examining the role of magnetic fields in plasma behavior and surface evolution of a Mg alloy with varied irradiances in a femtosecond laser treatment
Year: 2024
Authors: Dawood A., Khan M.A., Bashir S., Ayub A., Hayat A., Sanderson J.H., Chishti N.A.
Autors Affiliation: Govt Coll Univ, Ctr Adv Studies Phys CASP, Lahore 54000, Pakistan; Natl Excellence Inst Univ, Dept Phys, Islamabad 04524, Pakistan; Univ Waterloo, Dept Phys & Astron, Waterloo, ON N2L 3G1, Canada; Nazarbayev Univ, Dept Phys, Nur Sultan, Nur Sultan, Kazakhstan; Univ Campania Luigi Vanvitelli, Dept Math & Phys, I-81100 Caserta, Italy; Women Univ Mardan, Dept Phys, Khyber Pakhtunkhwa, Pakistan; Air Univ, Islamabad 44000, Pakistan.
Abstract: This paper reports the effect of a magnetic field on plasma parameters and surface structuring of the Mg alloy after laser irradiation. Femtosecond pulses of a Ti:sapphire laser system (800 nm, 35 fs, 1 KHz) are employed as the source of irradiation at various irradiances ranging from 0.011 PW / cm 2 to 0.117 PW / cm 2 to generate ablated Mg -alloy plasma. A transvers magnetic field (TMF) of strength 1.1 Tesla is employed to confine laser generated Mg plasma. All the measurements are performed with and without TMF. The two plasma parameters, i.e., excitation temperature (T exc ) and electron number density ( n e ) of Mg plasma, have been evaluated by laser -induced breakdown spectroscopy (LIBS) analysis. It is observed that the values of T exc and n e of laser produced plasma (LPP) of the Mg alloy are higher in the presence of a magnetic field as compared to the field free case. Both show initially an increasing trend with increasing laser irradiance and after attaining their respective maxima a decreasing trend is observed with the further increase of irradiance. The magnetic confinement validity is confirmed by analytically evaluating thermal beta ( beta t ), directional beta ( beta d ), confinement radius (R b ), and diffusion time (t d ) for LPP of the Mg alloy. To correlate the LPP parameters of the Mg alloy with surface modifications a field emission scanning electron microscope (FE-SEM) analysis is performed. It was revealed that structures like laser -induced periodic surface structures (LIPSSs), agglomerates, islands, large sized bumps, along with channels and multiple ablative layers are observed. Distinct and well-defined surface structuring is observed in the presence of TMF as compared to the field free case. It is concluded that by applying an external magnetic field during laser irradiation, controlled material surface structuring is possible for fabrication of nanogratings and field emitters where spatial uniformity is critically important. (c) 2024 Optica Publishing Group
Journal/Review: APPLIED OPTICS
Volume: 63 (13) Pages from: 3585 to: 3599
More Information: Funding. Higher Education Commission, Pakistan.KeyWords: Induced Breakdown Spectroscopy; Ambient Gas; Metal Nanoparticles; Ablation; Emission; Pressure; Agglomeration; Enhancement; Morphology; ThresholdDOI: 10.1364/AO.523804Citations: 2data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2025-05-18References taken from IsiWeb of Knowledge: (subscribers only)
