Surface-enhanced mid-infrared absorption spectroscopy using miniaturized-disc metasurface

Abstract

Surface-enhanced infrared spectroscopy is an important technique for improving the signal-to-noise ratio of spectroscopic material identification measurements in the mid-infrared fingerprinting region. However, the lower bound of the fingerprinting region receives much less attention due to a scarcity of transparent materials, more expensive sources, and weaker plasmonic effects. In this paper, we present a miniaturized metasurface unit cell for surface-enhanced infrared spectroscopy of the 15-$$\upmu$$ μ m vibrational band of CO$$_{2}$$ 2 . The unit cell consists of a gold disc, patterned along the edge with fine gaps/wires to create a resonant metamaterial liner. In simulation, our plasmonic metamaterial-lined disc achieves greater than $$4\times$$ 4 × the average field intensity enhancement of a comparable dipole array and a miniaturized size of $$\lambda _0/5$$ λ 0 / 5 using complex, 100-nm features that are patterned using 100-kV electron-beam lithography. In a simple experiment, the metamaterial-lined disc metasurface shows a high tolerance to fabrication imperfections and enhances the absorption of CO$$_{2}$$ 2 at 15 $$\upmu$$ μ m. The resonant wavelength and reflection magnitude can be tuned over a wide range by adjusting the liner feature sizes and the metasurface array pitch to target other vibrational bands. This work is a step toward low-cost, more compact on-chip integrated gas sensors.

Greenhouse Gas Detection Based on Infrared Nanophotonic Devices

“…It is worth noting that not all molecular vibrations give rise to infrared absorption, only vibrations that change in dipole moment can give rise to an observable infrared absorption spectrum. That molecule is considered to be infrared active [29].…”

“…It is an emerging material that combines optics and nanotechnology. Ashwin K. Iyer's team [29] reported on a study of surface-enhanced infrared absorption spectroscopy using micro-disc hypersurfaces [112] towards low-cost, more compact integrated gas sensors on a chip. This study presents a micro-hypersurface cell for surface-enhanced infrared spectroscopy of the 15 μm vibrational band of CO 2 .…”

Lifetime and Molecular Coupling in Surface Phonon Polariton Resonators

“…Surface polariton resonances with subdiffraction confinement form through the strong coupling between coherently oscillating charge and light. , Their advantages for applications in sensing , optoelectronics, − and active optics arise from their ability to localize electric fields to deep subdiffraction length scales. An active area of interest is surface-enhanced infrared absorption spectroscopy (SEIRA), which allows absorption spectroscopy to detect orders of magnitude smaller concentrations of materials , when compared with conventional infrared techniques. Surface plasmon polaritons (SPPs), which arise due to coupling between light and electrons, have been extensively studied for this application. , Still, their relatively short lifetime (hundreds of femtoseconds) limits achievable confinement and coupling. − This has motivated the search for longer lifetime polariton modes, including dielectric antennas, , Tamm hybrid structures, and surface phonon polaritons (SPhPs). , Surface phonon polaritons are particularly interesting due to their occurrence in the molecular fingerprint window from 6 to 20 μm. , Polar dielectric materials support them and arise due to coupling to polar optical phonons and light.…”

“… 1 , 2 Their advantages for applications in sensing 3 , 4 optoelectronics, 5 − 7 and active optics 8 arise from their ability to localize electric fields to deep subdiffraction length scales. An active area of interest is surface-enhanced infrared absorption spectroscopy (SEIRA), which allows absorption spectroscopy to detect orders of magnitude smaller concentrations of materials 9 , 10 when compared with conventional infrared techniques. Surface plasmon polaritons (SPPs), which arise due to coupling between light and electrons, have been extensively studied for this application.…”

Performance comparison and analysis of dimers metasurface structures under different materials based on fano resonance

“…Optical metasurface is an artificial array structure that can control the amplitude, phase and polarization states of the wavefront of the light field at the sub-wavelength scale flexibly [9,10]. Optical metasurfaces have good surface local performance and can lead to large surface electromagnetic enhancement by excitation of surface plasmon resonance, which is often applied in surface-enhanced Raman scattering [11], surface-enhanced infrared absorption spectroscopy [12,13]. Li et al [14] proposed a metasurface structure composed of three gold nanostrips arrayed in the dielectric waveguide, and realized the double-peak Fano resonance with Q factor 950 and 216, which were applied to the refractive index (RI) sensor, and their FOM values were 330 RIU −1 and 281 RIU −1 , respectively.…”