A. E. Ershov

Suppression of surface plasmon resonance in Au nanoparticles upon transition to the liquid state.

Significant suppression of resonant properties of single gold nanoparticles at the surface plasmon frequency during heating and subsequent transition to the liquid state has been demonstrated experimentally and explained for the first time. The results for plasmonic absorption of the nanoparticles have been analyzed by means of Mie theory using experimental values of the optical constants for the liquid and solid metal. The good qualitative agreement between calculated and experimental spectra support the idea that the process of melting is accompanied by an abrupt increase of the relaxation constants, which depends, beside electron-phonon coupling, on electron scattering at a rising number of lattice defects in a particle upon growth of its temperature, and subsequent melting as a major cause for the observed plasmonic suppression. It is emphasized that observed effect is fully reversible and may underlie nonlinear optical responses of nanocolloids and composite materials containing plasmonic nanoparticles and their aggregates in conditions of local heating and in general, manifest itself in a wide range of plasmonics phenomena associated with strong heating of nanoparticles.

Thermal effects in systems of colloidal plasmonic nanoparticles in high-intensity pulsed laser fields [Invited]

We have studied light induced processes in nanocolloids and composite materials containing ordered and disordered aggregates of plasmonic nanoparticles accompanied by their strong heating. A universal comprehensive physical model that combines mechanical, electrodynamical, and thermal interactions at nanoscale has been developed as a tool for investigations. This model was used to gain deep insight on phenomena that take place in nanoparticle aggregates under high-intensity pulsed laser radiation resulting in the suppression of nanoparticle resonant properties. Verification of the model was carried out with single colloidal Au and Ag nanoparticles and their aggregates.

Refractory titanium nitride two-dimensional structures with extremely narrow surface lattice resonances at telecommunication wavelengths

Regular arrays of plasmonic nanoparticles have brought significant attention over the last decade due to their ability to support localized surface plasmons (LSPs) and exhibit diffractive grating behavior simultaneously. For a specific set of parameters (i.e., period, particle shape, size, and material), it is possible to generate super-narrow surface lattice resonances (SLRs) that are caused by interference of the LSP and the grating Rayleigh anomaly. In this letter, we propose plasmonic structures based on regular 2D arrays of TiN nanodisks to generate high-Q SLRs in an important telecommunication range, which is quite difficult to achieve with conventional plasmonic materials. The position of the SLR peak can be tailored within the whole telecommunication bandwidth (from ≈ 1.26 μm to ≈ 1.62 μm) by varying the lattice period, while the Q-factor is controlled by changing nanodisk sizes. We show that the Q-factor of SLRs can reach a value of 2 × 103, which is the highest reported Q-factor for SLRs at tele...

Thermal limiting effects in optical plasmonic waveguides

Abstract We have studied thermal effects occurring during excitation of optical plasmonic waveguide (OPW) in the form of linear chain of spherical Ag nanoparticles by pulsed laser radiation. It was shown that heating and subsequent melting of the first irradiated particle in a chain can significantly deteriorate the transmission efficiency of OPW that is the crucial and limiting factor and continuous operation of OPW requires cooling devices. This effect is caused by suppression of particles surface plasmon resonance due to reaching the melting point temperature. We have determined optimal excitation parameters which do not significantly affect the transmission efficiency of OPW.

Temperature dependent elastic repulsion of colloidal nanoparticles with a polymer adsorption layer

The model of pairwise elastic repulsion of contacting colloidal nanoparticles with a rigid core and deformable shell is discussed. A simple analytical equation is applied for the energy of elastic repulsion of nanoparticles with arbitrary sizes and the elasticity moduli of self-healing polymer adsorption layers. The model is based on the representation of the absorption layer as a continuous medium that is elastically deformed upon the contact of nanoparticles. The major characteristic of this medium is the elasticity modulus. The magnitude of the elasticity modulus is determined from the condition of balance of the van der Waals attractive forces of nanoparticles and the elastic repulsion of their adsorption layers in the contact area, taking into account the temperature variations. We employed the kinetic approach to describe the dependence of the elasticity modulus on both the temperature and the rate of its change.

Thermal effects in systems of colloidal plasmonic nanoparticles in high-intensity pulsed laser fields [Invited]: publisher’s note

Thermal effects in systems of colloidal plasmonic nanoparticles in high-intensity pulsed laser fields [Invited] : publishers note (vol 7,pg 555, 2017)