Role of near-field enhancement in plasmonic laser nanoablation using gold nanorods on a silicon substrate: comment

The occurrence of plasmon resonances on metallic nanometer-scale structures is an intrinsically nanoscale phenomenon, given that the two resonance conditions (i.e., negative dielectric permittivity and large free-space wavelength in comparison with system dimensions) are realized at the same time on the nanoscale. Resonances on surface metallic nanostructures are often experimentally found by probing the structures under investigation with radiation of various frequencies following a trial-and-error method. A general technique for the tuning of these resonances is highly desirable. In this paper we address the issue of the role of local surface patterns in the tuning of these resonances as a function of wavelength and electric field polarization. The effect of nanoscale roughness on the surface plasmon polaritons of randomly patterned gold films is numerically investigated. The field enhancement and relation to specific roughness patterns is analyzed, producing many different realizations of rippled surfaces. We demonstrate that irregular patterns act as metal–dielectric–metal local nanogaps (cavities) for the resonant plasmonic field. In turn, the numerical results are compared to experimental data obtained via aperture scanning near-field optical microscopy.

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Analytical and Experimental Investigation of Laser-Nanosphere Interaction for Nanoscale Surface Modification

Heat Transfer, Volume 2 ◽

10.1115/imece2004-61983 ◽

2004 ◽

Author(s):

Alex J. Heltzel ◽

Senthil Theppakuttai ◽

John R. Howell ◽

Shaochen Chen

Keyword(s):

Silicon Substrate ◽

Substrate Surface ◽

Near Field ◽

Pulsed Laser ◽

Field Enhancement ◽

Laser Wavelength ◽

Nanometer Scale ◽

Silica Nanospheres ◽

Size Parameter ◽

532 Nm

An investigation on the features created on a silicon substrate by the irradiation of nanospheres on the substrate surface with a pulsed laser is presented. Silica nanospheres of diameter on the order of laser wavelength are deposited on silicon substrate and irradiated with a pulsed Nd: YAG laser. As a result, nanofeatures are created on the surface by the melting and resolidification of silicon. The experiment is repeated for different laser wavelengths (532 nm, and 355 nm), sphere diameters (640 nm, and 1.76 μm) and laser energies, and the effect of each of these parameters on the features created are studied. An analytical model based on Mie Theory complements the results. The model includes all evanescent terms and does not rely on either far field or size-parameter approximations. The predicted intensity distributions on the substrate indicate a strong near field enhancement confined to a very small area (nanometer scale). The results correlate well with the feature geometries obtained in the experiment.

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The role of morphology and coupling of gold nanoparticles in optical breakdown during picosecond pulse exposures

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.7.79 ◽

2016 ◽

Vol 7 ◽

pp. 869-880 ◽

Cited By ~ 8

Author(s):

Yevgeniy R Davletshin ◽

J Carl Kumaradas

Keyword(s):

Gold Nanoparticles ◽

Laser Pulse ◽

Near Field ◽

Optical Breakdown ◽

Field Enhancement ◽

The Finite Element Method ◽

Breakdown Threshold ◽

Plasma Dynamics ◽

The One

This paper presents a theoretical study of the interaction of a 6 ps laser pulse with uncoupled and plasmon-coupled gold nanoparticles. We show how the one-dimensional assembly of particles affects the optical breakdown threshold of its surroundings. For this purpose we used a fully coupled electromagnetic, thermodynamic and plasma dynamics model for a laser pulse interaction with gold nanospheres, nanorods and assemblies, which was solved using the finite element method. The thresholds of optical breakdown for off- and on-resonance irradiated gold nanosphere monomers were compared against nanosphere dimers, trimers, and gold nanorods with the same overall size and aspect ratio. The optical breakdown thresholds had a stronger dependence on the optical near-field enhancement than on the mass or absorption cross-section of the nanostructure. These findings can be used to advance the nanoparticle-based nanoscale manipulation of matter.

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