Development Of Plasmonics Research Articles

Preparation and SERS Study of Triangular Silver Nanoplates

Metal nanostructures have unique properties that differ from their bulk structures. Of the metals, silver has probably play the most important role in the development of plasmonics, and its unique properties make it well-suited for most of the next-generation plasmonic technologies. Among the various silver nanostructures, silver nanoplates have attracted considerable attention because of their shape-dependent optical properties, which have been applied in surface enhanced Raman spectroscopy (SERS). In this study, the direct chemical reduction route was used to prepare silver nanoplates. Then the influence of experimental conditions on the morphologies of silver nanoplates has been studied. The results has been proved by the UV-vis spectrum and the transmission electron microscope images of the triangular silver nanoparticle. Finally, the silver nanoplates have been applied in SERS properties with Rhodamine 6G as the probe molecules. It was found that the SERS enhancement ability of the silver nanoplates is remarkable. By comparing the advantages and disadvantages of solid Raman and liquid Raman tests, Liquid Raman test is considered to be simpler and more convenient, with high performance price ratio and extremely high application value in the future.

In operando plasmonic monitoring of electrochemical evolution of lithium metal

The recent renaissance of lithium metal batteries as promising energy storage devices calls for in operando monitoring and control of electrochemical evolution of lithium metal morphologies. While the development of plasmonics has led to significant advancement in real-time and ultrasensitive chemical and biological sensing and surface-enhanced spectroscopies, alkali metals featured by ideal free electron gas models have long been regarded as promising plasmonic materials but seldom been explored due to their high chemical reactivity. Here, we demonstrate the in operando plasmonic monitoring of the electrochemical evolution of lithium metal during battery cycling by taking advantage of selective electrochemical deposition. The relationships between the evolving morphologies of lithium metal and in operando optical spectra are established both numerically and experimentally: Ordered growth of lithium particles shows clear size-dependent reflective dips due to hybrid surface plasmon resonances, while the formation of undesirable disordered lithium dendrites exhibits a flat spectroscopic profile with pure suppression in reflection intensity. Under the in operando plasmonic monitoring enabled by the microscopic morphology of metal, the differences of lithium evolutionary behaviors with different electrolytes can be conveniently identified without destruction. At the intersection of energy storage and plasmonics, it is expected that the ability to actively control and in operando plasmonically monitor electrochemical evolution of lithium metal can provide a promising platform for investigating lithium metal behavior during electrochemical cycling under various working conditions.

Encoding orbital angular momentum of light in magnets

Breaking the diffraction limit and focusing laser beams to subwavelength scale are becoming possible with the help of recent developments in plasmonics. Such subwavelength focusing bridges different length scales of laser beams and matter. Here we consider optical vortex, or laser beam carrying orbital angular momentum (OAM) and discuss potential subwavelength magnetic phenomena induced by such laser. On the basis of numerical calculations using Landau-Lifshitz-Gilbert equation, we propose two OAM-dependent phenomena induced by optical vortices, generation of radially anisotropic spin waves and generation of topological defects in chiral magnets. The former could lead to the transient topological Hall effect through the laser-induced scalar spin chirality, and the latter reduces the timescale of generating skyrmionic defects by several orders compared to other known means.

Laser-induced plasmonic colours on metals

Plasmonic resonances in metallic nanoparticles have been used since antiquity to colour glasses. The use of metal nanostructures for surface colourization has attracted considerable interest following recent developments in plasmonics. However, current top-down colourization methods are not ideally suited to large-scale industrial applications. Here we use a bottom-up approach where picosecond laser pulses can produce a full palette of non-iridescent colours on silver, gold, copper and aluminium. We demonstrate the process on silver coins weighing up to 5 kg and bearing large topographic variations (∼1.5 cm). We find that colours are related to a single parameter, the total accumulated fluence, making the process suitable for high-throughput industrial applications. Statistical image analyses of laser-irradiated surfaces reveal various nanoparticle size distributions. Large-scale finite-difference time-domain computations based on these nanoparticle distributions reproduce trends seen in reflectance measurements, and demonstrate the key role of plasmonic resonances in colour formation.

Plasmonic Sensors for Disease Detection - A Review

Surface Plasmon Resonance (SPR) and Localized Surface Plasmon Resonance (LSPR) have become powerful bio-sensing techniques. These techniques allow for rapid and ultra-sensitive detection of biological analytes with applications in medical diagnostics, environmental monitoring, and food safety. Plasmonic sensors are fabricated using metal nanoparticles, metal nanostructures or a combination of both. With major advancements in the area of nano synthesis, the development of plasmonic sensors has expanded significantly. Plasmonic platforms offer a viable substitute to detection techniques such as Enzyme Linked Immunosorbent Assay (ELISA) and Polymerase Chain Reaction (PCR) in some cases and complement them in many others. Most of the state-of-the-art plasmonic biosensors can measure binding affinity and kinetic rates in real time from any molecule that can change its refractive index. Other developments in plasmonics include the use of metamaterials that operate in the visible and infra-red region. In this review, we will briefly cover the developments in the last few years in plasmonics as it relates to disease detection

Novel Fabrication of Au Nanoparticle Film on a Polyelectrolyte‐coated Glass for Efficient Surface‐enhanced Raman Scattering#

In this paper, we report a novel method for the growth of gold nanoparticles on a polyelectrolyte‐coated glass and its application as a surface‐enhanced Raman scattering (SERS) substrate. Gold nanoparticles were readily grown on a polyelectrolyte‐coated substrate using butylamine as the reductant of HAuCl4 . The Au nanoparticles formed on the polyelectrolyte‐coated substrate exhibited superior SERS activity compared to an electrochemically roughened Au substrate or a vacuum‐evaporated Au film. In addition, our Au substrate shows excellent reproducibility and noticeable stability as an SERS substrate. The proposed strategy is simple, cost effective, and reproducible for the mass production of gold nanoparticles films, irrespective of the type of the underlying substrates, which therefore are useful in the development of plasmonics and SERS‐based analytical devices.

High-efficiency surface plasmon polariton source

The increasing application of plasmonic devices causes the requirement of high-efficiency surface plasmon polariton sources. Here, we present a new surface plasmon polariton coupler based on double nanoslits. By carefully choosing the geometry parameters of the structure, the coupling efficiency can be greatly enhanced through constructive interference between the double or multislits and the input surface modulation. The good functionalities of the device such as low noise, unidirectionality and high efficiency indicate that such a structure may be a good choice as a surface plasmon polariton source for rapid development of plasmonics.