Theoretical Study of Gold Nanoparticles Randomly Dispersed on a Dielectric/Gold Substrate.

We theoretically study random arrangements of cylindrical gold nanoparticles (NPs) deposited on a dielectric/gold substrate. We use two methods, namely the Finite Element Method (FEM) and the Coupled Dipole Approximation (CDA) method. The FEM is increasingly used to analyze the optical properties of NPs, but calculations for arrangements containing a large number of NPs have a high computational cost. On the contrary, the CDA has the advantage to drastically reduce the computation time and the memory demand compared to the FEM. Nevertheless, as the CDA involves modeling each NP as a single electric dipole through the polarizability tensor of a spheroidal-shaped NP, it may be an insufficiently accurate method. Therefore, the main purpose of this article is to verify the validity of using the CDA in order to analyze such a kind of nanosystems. Finally, we capitalize on this methodology to draw some tendencies between statistics of NPs' distributions and the plasmonic properties.

Impact of SiO2 Particles in Polyethylene Textile Membrane for Indoor Personal Heating.

Keeping the human body in a thermal comfort state inside a room has become a challenge in recent years. While the most common strategy is to heat buildings, it requires a lot of energy. Reducing this energy consumption will have positive impacts, both economically and environmentally. We propose here to act directly on the personal thermal heating of the human body, by modulating the absorption and transmission properties of a synthetic polymer membrane in the mid-infrared (MIR). We show numerically that 5% SiO2 submicron particles inserted in polyethylene (PE) and nanoporous polyethylene (nanoPE) membranes increase the radiative heating of the membrane, reducing the required ambient temperature of a room by more than 1.1 °C. The proposed membrane can be flexible enough to be easily integrated into conventional textiles.

Polymer photonic crystal membrane for thermo-regulating textile.

We study numerically the absorption and scattering properties of a polymer photonic membrane to thermoregulate the human body microclimate which corresponds to the area between the skin and a textile. We first show that the structuration of the absorbing photonic membrane with air holes leads to a modulation of the optical spectrum in the Mid-Infrared range. Indeed, we show that the membrane is able to modulate the transmission amplitude by 28% in benefit or deficit of both the absorption and reflection. We then studied the thermal balance between the human body and the surrounding environment through the photonic membrane. We found that, compared to a regular membrane, the photonic crystal structure behaves as a heating component that offers the possibility to reduce the temperature of the room up to +1 °C. The membrane is flexible, low cost, 3D-printable, free of metallic particles, and can easily be added to usual textiles.

Plasmon cross transmission.

Plasmon cross transmission avoids the frontal collision between two plasmons traveling in opposite directions along a guide. The guide is made out of equidistant identical metal dots. Thanks to two resonator dots, the plasmon frontal impact is avoided by transmission of the two plasmons from the input guide to an output one. The resonator and guide dots are identical in size and metal composition. The dipole-dipole interactions are restricted to first nearest neighbors. A convenient metal doping is assumed to compensate exactly all attenuations. The parameters are the nearest neighbor distances between the dots. These distances are rescaled to the chain nearest neighbor distance d. The system has two symmetry mirror planes. This simple model enables us to obtain two analytic tuning relations for the plasmon cross transmission. The intensities of the transmitted signals versus kd, where k is the plasmon propagation vector, are also given.

Plasmonic properties of silver nanostructures coated with an amorphous silicon-carbon alloy and their applications for sensitive sensing of DNA hybridization.

The use of an amorphous silicon-carbon alloy overcoating on silver nanostructures in a localized surface plasmon resonance (LSPR) sensing platform allows for decreasing the detection limit by an order of magnitude as compared to sensors based on gold nanostructures deposited on glass. In addition, silver based multilayer structures show a distinct plasmonic behaviour as compared to gold based nanostructures, which provides the sensor with an increased short-range sensitivity and a decreased long-range sensitivity.