Title:	Enhancement of optical emission and ion currents in a laser produced silicon plasma by femtosecond laser-induced periodic surface structuring
Authors:	Anoop, K K Verma, Nancy Joy, Nithin Harilal, S.S. Philip, Reji
Issue Date:	Jun-2018
Publisher:	American Institute of Physics
Citation:	Physics of Plasmas. 2018, Vol. 25. p063304
Abstract:	Laser-induced periodic surface structuring is a powerful technique for modifying the surface properties of solids. Using ultrashort pulses from a Ti:sapphire laser (800 nm, 100 fs), we have fabricated nanoscale order laser-induced periodic surface structures (LIPSSs) on a silicon (100) surface. The LIPSS patterns are found to be strongly dependent on the laser pulse energy, state of polarization, number of shots delivered on the target, and the ambient pressure. The role of laser wavelength is studied by using the second harmonic output (400 nm) also for fabrication. Large area (5 × 4 mm2) surface structuring has been carried out at atmospheric pressure after optimizing the laser parameters at 800 nm. The patterned silicon surface shows a substantial reduction in the reflection of incident light over a wide range of wavelengths, in comparison to plain silicon. Moreover, when used for laser induced breakdown spectroscopy experiments, enhanced optical emission and ion current have been observed from the patterned surface. This indicates that the coupling of laser energy to the surface is enhanced in the case of patterned silicon. While spectral lines emitted by doubly ionized silicon have been observed from the patterned surface, the plain surface gives lines from singly ionized silicon only. A discernible enhancement has been measured in both optical (50%–90%) and electrical (34%) signals from the plasma generated on the patterned surface. These results confirm that LIPSS is a versatile method for enhancing the coupling of laser energy onto irradiated solid surfaces
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/6971
ISSN:	070-664X 1089-7674 (online)
Alternative Location:	https://doi.org/10.1063/1.5038913
Copyright:	2018 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Appears in Collections:	Research Papers (LAMP)

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