Formation of metal nanoparticles of various sizes in plasma plumes produced by Ti:sapphire laser pulses

Abstract

In this paper, an experimental study on generation of nanoparticle various sizes using Ti:sapphire laser pulses, is reported. Nanoparticle formation in plasma plumes of metals like silver and copper, expanding in vacuum, has been studied using stretched pulses of 300 ps duration [subnanoseconds (sub-ns)] from a Ti:sapphire laser. It has been compared with the nanoparticle formation (of the same materials) when compressed pulses of 45 fs duration were used under similar focusing conditions. Nanoparticle formation is observed at intensities as high as 2×1016 W/cm2. The structural analysis of the nanoparticle deposition on a silicon substrate showed that, using 45 fs pulses, smaller nanoparticles of average size ∼20 nm were generated, whereas on using the sub-ns pulses, larger particles were produced. Also, the visible light transmission and reflection from the nanoparticle film of Ag on glass substrate showed surface plasmon resonance (SPR). The SPR curves of the films of nanoparticles deposited by femtosecond pulses were always broader and reflection/transmission was always smaller when compared with the films formed using the sub-ns pulses, indicating smaller size particle formation by ultrashort pulses. Thus, it has been demonstrated that variation in the laser pulse duration of laser offers a simple tool for varying the size of the nanoparticles generated in plasma plumes.

Effects of Different Laser Pulse Regimes (Nanosecond, Picosecond and Femtosecond) on the Ablation of Materials for Production of Nanoparticles in Liquid Solution

“…Finally, the target ejected the cluster precursors directly to the liquid solution and the plasma plume is confined to a smaller volume. Chakravarty et al [42] concluded that the smaller size of silver and copper nanoparticles can be produced by ultra-short laser pulse duration in comparison with the subnanosecond laser pulse duration. It was shown that broader surface plasmon resonance (SPR) and smaller reflection/transmission of silver and copper nanoparticles deposited by femtosecond laser in comparison with those deposited by subnanosecond laser indicating smaller size particle generation by ultra-short pulse durations.…”

Dynamics of femtosecond laser produced tungsten nanoparticle plumes

“…Laser ablation plumes are well known as a source of nanoparticle generation and intense research is underway in the last few years especially for identifying physical mechanisms leading to nanoparticle production though it is still unclear. [6][7][8][9][10][11][12][13][14][15][16] In order to understand the processes leading to nanoparticle formation, the mechanism of plasma plume generation from the target material under laser irradiation and the interaction of the resulting plume with the ambient atmosphere in the plasma chamber should be studied in detail. 17,18 The properties of laser ablation depends on numerous laser, target and environmental parameters and hence there is a possibility of precise control over nanoparticles size as well as their size distribution.…”

Large-Scale Fabrication of Nanostructure on Bio-Metallic Substrate for Surface Enhanced Raman and Fluorescence Scattering

“…The energetic melting fluid with high pressure was thereby created. Then the fluid expanded into the air, the mechanical bonds were broken by the strain associated with the fast expansion of melting, which resulted in fluid fragmentation [22,23]. The particle size was measured manually using an open source image processing software ImageJ (NIH, Bethesda, MD, USA), where a total of ∼100 nano-particles were measured to obtain an average dimension.…”