High‐ Q Plasmonic Fano Resonance for Multiband Surface‐Enhanced Infrared Absorption of Molecular Vibrational Sensing

power consumption and minimizing cross-talk (maintain signal fidelity). As a result, terabit data communication can be made feasible with the help of broadband all-optical devices and circuits. [4] The technology for designing optical components and circuits operating at visible and NIR wavelengths has matured significantly over the last several decades, ensuring their widespread integration. While we can work toward improving data transmission rates of existing communication technology, shortage of spectral bandwidth for data transmission has become a looming problem over time. This has motivated researchers to seek out previously unused portions of the electromagnetic spectrum. The "terahertz gap" (≈30 µm-3 mm) has attracted considerable attention from researchers seeking to bridge the gap between the optical/IR and microwave spectrum. [5,6] Similar to the optical domain, the invention, optimization, and commercialization of discrete components such as sources, modulators, and detectors are necessary for the widespread use and integration of terahertz technologies. Electronic means of terahertz generation utilizing semiconductors (Si, GaAs) IMPATT [7] and Gunn diodes [8] have been developed. In conjunction with a frequency doubler/ tripler circuits, they typically operate on the lower end of the terahertz spectrum (0.1-1 THz); although the power output at higher frequency multiples might be significantly lower as compared to its fundamental mode. Additionally, InGaAs/ InP HBTs and InP HEMTs with cutoff frequencies >600 GHz have been demonstrated. [9,10] The advent of femtosecond lasers has paved the way for the generation of terahertz radiation via photoconductive switches, [11] photo-Dember effect [12,13] and nonlinear optical rectification in organic and inorganic crystals. [14][15][16] Femtosecond lasers have helped develop time domain terahertz systems that have been instrumental in ultrafast spectroscopy to study transient carrier dynamics of semiconductors. Development of terahertz quantum cascade lasers (THz-QCL) employing intersubband transitions in AlGaAs/GaAs quantum wells [17][18][19][20] is a notable milestone in terahertz lasing. In a complementary fashion, terahertz detection could be performed by electro-optic sampling in nonlinear crystals, [21] photoconductive antennas on low-temperature GaAs, [22,23] plasma wave oscillation in a field-effect channel, [24,25] etc. Finally, akin to the compact and economic components available at optical frequencies for the generation, manipulation, and detection, terahertz technology requires Terahertz waves spanning over the 0.1 to 10 THz region of the electromagnetic spectrum have attracted significant attention owing to a variety of potential applications such as short-range high-speed data transmission, noninvasive screening and detection, materials characterization, spectroscopy, etc. This has resulted in massive strides in the development of essential system components such as broadband terahertz sources, detector arrays with high responsivity, as well as...

Section: Sensing and Spectroscopy Of Moleculesmentioning

confidence: 99%

2D Materials for Terahertz Modulation

Gopalan

Sensale‐Rodriguez

2019

“…Based on the interference of the radiant and subradiant LSP modes, a variety of metallic nanostructures were designed to engineer the Fano profiles, and the Fano sensors were realized in the past decades . For example, in the single split‐ring structures ( Figure a), both of the radiant and subradiant LSP modes were supported due to the structural symmetry breaking, and the interference of these two modes gave rise to the Fano resonance (linewidth of Δλ ≈ 170 nm) .…”

Section: Plasmonic Sensors Based On Fano Resonancesmentioning

confidence: 99%

“…The detection and recognition of small enveloped RNA viruses (vesicular stomatitis virus and pseudotyped Ebola) as well as large enveloped DNA viruses (vaccinia virus) within a dynamic range spanning from 10 6 to 10 9 PFU mL −1 (plaque forming unit per milliliter) were experimentally demonstrated. Recently, Singh and co‐workers designed a metasurface, which consisted of multiple concentric annular apertures with a rectangular aperture overlapping the outermost annular aperture in a 100 nm thick Au film, to realize the Fano resonances at the mid‐infrared range from 4 to 10 µm . The Fano resonances around 5.72 and 4.61 µm stemmed from the interference of the azimuthal quadrupolar mode ( m = 4) of the annular aperture with the dipolar and quadrupolar modes of the rectangular aperture.…”

Section: Plasmonic Sensors Based On Fano Resonancesmentioning

confidence: 99%

Plasmonic Sensing and Modulation Based on Fano Resonances

Chen

Gan

Wang

et al. 2018

113

The rapid developments in nanotechnology and plasmonics allow the manipulation of light at nanometer scales, such as light propagation and resonances. Differing from the symmetric Lorentzian‐like profiles in the conventional resonances, Fano resonances, which originate from the interference of different resonant modes, exhibit obviously asymmetric spectral profiles. Based on lineshape engineering, the Fano resonances with sharp asymmetric profiles exhibit a small linewidth and a high spectral contrast by exploiting different mechanisms and designing various metallic nanostructures. Both of the above properties in the sharp Fano resonances have significant applications in nanoscale plasmonic sensors and modulators. This review summarizes the underlying mechanism of the Fano resonances in various metallic nanostructures. Then, practical applications of the Fano resonances in nanoscale plasmonic sensing and modulation are reviewed. At last, the development and challenges of plasmonic sensing and modulation based on Fano resonances are discussed.

Section: Applicationsmentioning

confidence: 99%

“…The high‐ Q Fano resonators exhibit spectrally tunable single and multiple Fano resonances by changing the polarization of the incident light. The realization of such high‐ Q Fano resonance allowed for the proof‐of‐concept demonstration of Fano resonators (with a modified geometrical structure—inclusion of multiple concentric ring apertures) as shown in Figure f for ultrasensitive detection of molecular vibrational modes of poly(methyl methacrylate) (PMMA) using surface‐enhanced infrared absorption spectroscopy (SEIRA) . When the position of the Fano resonance spectrally aligns with the vibrational modes of COC and CH; CH 2 and CH 3 ; and CO; spectral fingerprints that were absent in the reference spectra are precisely identified from the amplified spectra.…”

Section: Applicationsmentioning

confidence: 99%

Shaping High‐Q Planar Fano Resonant Metamaterials toward Futuristic Technologies

Lim

Manjappa

Pitchappa

et al. 2018

Self Cite

Advances in plasmonic metamaterials have been rapidly evolving with innovations aimed at developing metadevices for real-world applications. In reality, energy losses in plasmonic systems are prevalent and it is of paramount importance to come up with solutions that could overcome the limitations that impede further advancements toward the miniaturization of optoelectronic metadevices. High-Q Fano resonance as a scattering phenomenon can be easily triggered by introducing asymmetry into plasmonic systems, and thus it offers a simple approach for reducing radiative losses through lineshape engineering. High-Q Fano resonance possesses narrow linewidth and intensely confined electromagnetic fields, which makes it viable for widespread applications. The purpose of this review is to consolidate the current advances and contributions that high-Q Fano resonance has made in the metamaterial community. Two general modes of energy loss including radiative and nonradiative losses are introduced and possible ways to overcome these challenges are examined. Furthermore, applications based on high-Q Fano resonance including sensors, lasing spasers, and optical switches are discussed, embracing the future of Fano resonance based high performance photonic technologies.