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 ${0.011}\;{{\rm PW/cm}^2}$ to ${0.117}\;{{\rm PW/cm}^2}$ 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 (${{\rm T}_{{\rm exc}}}$) 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 ${{\rm T}_{{\rm exc}}}$ 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 (${{\rm R}_b}$), and diffusion time (${{\rm t}_d}$) 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.

© 2024 Optica Publishing Group

Laser-induced breakdown spectroscopy of aluminum plasma in the absence and presence of magnetic field

Naveed Ahmed Chishti, Shazia Bashir, Asadullah Dawood, and Muhammad Asad Khan
Appl. Opt. 58(4) 1110-1120 (2019)

Accurate determination of plasma temperature and electron density using a reference target: one-point calibration LIBS elemental analysis of alloy samples

Huiling Zeng, Runhua Li, and Yuqi Chen
Appl. Opt. 63(2) 338-344 (2024)

Optical emission from laser-induced breakdown plasma of solid and liquid samples in the presence of a magnetic field

Virendra N. Rai, Awadhesh K. Rai, Fang-Yu Yueh, and Jagdish P. Singh
Appl. Opt. 42(12) 2085-2093 (2003)

Optical emission enhancement of laser-produced copper plasma under a steady magnetic field

Yu Li, Changhong Hu, Hanzhuang Zhang, Zhankui Jiang, and Zhongshan Li
Appl. Opt. 48(4) B105-B110 (2009)

Investigation of number density, temperature, and kinetic energy of nanosecond laser-induced Zr plasma species for self-generated electric and magnetic fields in axial expansion of plume

Tayyaba Sajid, Shazia Bashir, Mahreen Akram, Maira Razzaq, Mubashir Javed, and Khaliq Mahmood
J. Opt. Soc. Am. B 39(8) 1986-2005 (2022)