Araştırma Alanları

Fizik

Plasmonic nanoparticles support surface plasmon resonances (SPRs), which are collective oscillations of the electronic charge density localized at the surface of metallic structures. The optical properties of these metallic nanostructures differ from the optical response of the same metallic material in bulk. Among many plasmonic nanostructures, metallic nanoantennas exhibit unique optical properties derived from the huge enhancement and confinement of the electromagnetic fields at the nanoscale dimension associated with the excitation of localized surface plasmon resonances (LSPR). The LSPR properties of plasmonic nanoantennas are governed by three major structural designs: tunable dielectric-control nanostructures, nanoparticles with tunable gaps, and nanostructures self-tunable by charge carriers.

The energies of LSPRs also depend on the geometry of the nanoantenna structure, as well as their sensitivity to the dielectric environment. Thus, depending on the particular property of interest and, by engineering the shape, the materials or the geometric configuration, a huge variety of nanoantennas has been synthesized, such as nanorings, nanoparticle dimers, nanoshells, nanorods, or nanostars.

Plasmonic nanoantennas have played a significant role in enhancing the efficiency of optoelectronic and photonic devices. In a coupled linear and nonlinear environment these nanoantennas display enhanced characteristics and features that enable them to employ as an effective tool for biological fingerprinting and biosensing technology. Nanoantennas have also become a potential source of confined light in nanolaser systems.

Metallic nanoparticles exhibit improved scattering and absorption properties at resonant electromagnetic energy while restricting electromagnetic fields in nanosize areas known as hot-spots. The highly concentrated electric field of hotspots can be employed to improve the interaction of light and matter at the nanoscale. Furthermore, the field localization and enhancement capabilities of metallic nanoparticles have been investigated in the spectroscopy of extremely tiny molecules. This is known as field-enhanced spectroscopy. The tunability of the electromagnetic resonance of metallic nanoparticles with size, shape, and material composition allows access to molecular vibrations under a wide range of conditions.

Surface Enhanced Raman Spectroscopy (SERS) and Surface Enhanced Infrared Absorption Spectroscopy (SEIAS) are two well-known configurations for performing field-enhanced spectroscopy. While SERS investigates enhanced electromagnetic scattering by molecules, mediated by the field-boosting capability of metallic nanoparticles. On the other hand SEIRA focuses on enhanced electromagnetic radiation absorption by molecules.

We study theoretically the optical response of Refractory Transition Metal Nitride (RTMN) for optimizing them to perform field-enhanced spectroscopy.