Plasmonic 2D Materials: Overview, Advancements, Future Prospects and Functional Applications

Plasmonics is a technologically advanced term in condensed matter physics that describes surface plasmon resonance where surface plasmons are collective electron oscillations confined at the dielectric-metal interface and these collective excitations exhibit profound plasmonic properties in conjunction with light interaction. Surface plasmons are based on nanomaterials and their structures; therefore, semiconductors, metals, and two-dimensional (2D) nanomaterials exhibit distinct plasmonic effects due to unique confinements. Recent technical breakthroughs in characterization and material manufacturing of two-dimensional ultra-thin materials have piqued the interest of the materials industry because of their extraordinary plasmonic enhanced characteristics. The 2D plasmonic materials have great potential for photonic and optoelectronic device applications owing to their ultra-thin and strong light-emission characteristics, such as; photovoltaics, transparent electrodes, and photodetectors. Also, the light-driven reactions of 2D plasmonic materials are environmentally benign and climate-friendly for future energy generations which makes them extremely appealing for energy applications. This chapter is aimed to cover recent advances in plasmonic 2D materials (graphene, graphene oxides, hexagonal boron nitride, pnictogens, MXenes, metal oxides, and non-metals) as well as their potential for applied applications, and is divided into several sections to elaborate recent theoretical and experimental developments along with potential in photonics and energy storage industries.

Trends in the development of sensor devices based on surface plasmon resonance (Review)

Trends in the development of modern sensory devices based on surface plasmon resonance (SPR) are considered. The basic principles of construction of SPR sensor are given. For excitation of surface plasmons on the surface of sensitive elements of biosensory, a prism of total internal reflection is used or a dielectric substrate are used. A thin (dozens nm) film of high-conductive metal (mainly gold or silver) is applied to the working surface of the prisms or dielectric substrate. In a typical observation experiment, SPR is measured dependence on the angle of increasing light intensity, reflected by the resonance sensitive surface of the prism (chip). The optical schemes and principles of work of various SPR sensors are considered: - SPR Sensors with angular modulation, which are the most commonly used method based on the corner registration, in which the SPR occurs. The surface of the metal film is irradiated by monochromatic light and scans on a certain range of angles. There is a kind of SPR sensors with angular modulation, in which there is no mechanical scan of the angle of fall. Such sensors are entirely necessary for excitation of PPRs a set of angles is obtained due to a divergent or convergent light beam. - PPR sensors with a wavelength modulation is based on fixing an angle of falling light at a certain value and modulation of the wavelength of the incident light. Excitation of surface plasmons leads to a characteristic failure in the spectrum of reflected radiation. - Phase sensitive SPR sensors in which a change in the phase of the light wave associated with the surface plasma is measured on one corner of the fall and the wavelength of the light wave and is used as the output signal. - SPR imaging sensors in which the Technology of SPR imaging (SPRi) combines the sensitivity of the SPR with spatial image capabilities. The SPRI circuit uses as a fixed angle (as a rule, a slightly left angle of the SPR) and a fixed wavelength to measure changes in the reflection ability (Δ% R) that occur when the curve of the SPR is shifted due to the change in the refractive index above the surface of the sensor element. - SPR imaging sensors polarization contrast. In order to improve the quality of high-performance SPR imaging sensors in terms of sensitivity and resolution, the method of polarization contrast is used Disadvantages and advantages of SPR sensors are constructed with different principles are considered. The design and prospect of the use of achromatic and suburchast wave plates in the PPR imaging sensors with polarization contrast are considered.

Guiding and routing surface plasmons with transformation-invariant metamaterials

Rough metallic surfaces cause severe scattering to surface plasmon polaritons (SPPs), thereby limiting the SPP transmission efficiency. Here, we propose a general scheme to design ultra-compact plasmonic routers that can confine and guide SPPs on arbitrarily shaped rough surface. Our strategy makes use of recently proposed transformation-invariant metamaterials. To illustrate the advantages of this approach, we perform finite-element simulations, showing that the performance of the designed surface-wave router is robust against the change in thickness. As a result, a λ/6-thick transformation-invariant metamaterial layer can significantly suppress scattering from arbitrarily shaped metallic bumps or crevices. We also give a blueprint to implement such ultracompact surface-wave routers based on periodic metal/ epsilon-near-zero (ENZ) material stackings.