Metasurfaces for Sensing Applications: Gas, Bio and Chemical

Abstract

Performance of photonic devices critically depends upon their efficiency on controlling the flow of light therein. In the recent past, the implementation of plasmonics, two-dimensional (2D) materials and metamaterials for enhanced light-matter interaction (through concepts such as sub-wavelength light confinement and dynamic wavefront shape manipulation) led to diverse applications belonging to spectroscopy, imaging and optical sensing etc. While 2D materials such as graphene, MoS2 etc., are still being explored in optical sensing in last few years, the application of plasmonics and metamaterials is limited owing to the involvement of noble metals having a constant electron density. The capability of competently controlling the electron density of noble metals is very limited. Further, due to absorption characteristics of metals, the plasmonic and metamaterial devices suffer from large optical loss. Hence, the photonic devices (sensors, in particular) require that an efficient dynamic control of light at nanoscale through field (electric or optical) variation using substitute low-loss materials. One such option may be plasmonic metasurfaces. Metasurfaces are arrays of optical antenna-like anisotropic structures (sub-wavelength size), which are designated to control the amplitude and phase of reflected, scattered and transmitted components of incident light radiation. The present review put forth recent development on metamaterial and metastructure-based various sensors.

Towards Highly Efficient Nitrogen Dioxide Gas Sensors in Humid and Wet Environments Using Triggerable-Polymer Metasurfaces

“…For our study, we chose the POEGMA polymer functionalized with a NO -reactive monomer known as PAPUEMA [ 34 ]. The thickness of the polymer represents a degree of freedom which is subject to optimization: as the thickness increases, so does the sensitivity to NO molecules, however, as the thickness reaches several times the penetration depth, the interaction with the metasurface pattern layered underneath it is no longer possible, and the whole architecture attains the behavior of the upper surface of the NO -sensitive polymer layer [ 38 ]. The layering scheme is presented in Figure 1 a.…”

Beyond Conventional Sensing: Hybrid Plasmonic Metasurfaces and Bound States in the Continuum

“…Plasmonic nanostructures have shown great potential for sensing applications due to their ability to confine light into nanoscale volumes, leading to high sensitivity and selectivity [ 41 , 42 , 43 , 44 , 45 , 46 ]. The spectral tunability of plasmonic nanostructures is limited by the intrinsic properties of the plasmonic materials and the geometrical design of the nanostructure.…”

Plasmonic Perfect Absorber Utilizing Polyhexamethylene Biguanide Polymer for Carbon Dioxide Gas Sensing Application

“…For sensing the CO 2 gas, a functional layer of PHMB is deposited over the top of LiNbO 3 , which is a member of the guanidine polymer family and is known for capturing the molecules of CO 2 by sensing its different concentrations at room temperature and normal atmospheric pressure [ 50 ]. Moreover, it is used due to its ability to vary its refractive index in response to an ambient change in the concentration of CO 2 gas in the environment, as well as due to its unique property of effectively sensing CO 2 gas without the need for water vapor as a catalyst to make CO 2 molecules heavier for better sensitivity calculations [ 51 ].…”