Metamaterial Perfect Absorber Research Articles

Genetic optimization of terahertz metamaterial absorber for improved absorption and quality factor

Terahertz metamaterial absorbers are typically comprised of an array of sub-wavelength meta-atoms, a dielectric spacer layer and a ground plane. The absorption and quality factor are two of the most important performance metrics for various advanced applications, such as THz communication, sensing, and imaging. However, a large number of structural parameters in the meta-atom make the design approach based on physical intuition and parameter sweep impractical and difficult. In this paper, we report an intelligent design methodology based on the genetic algorithm that facilitates the optimization of an air-spaced terahertz metamaterial absorber to improve its absorption and quality factor. The presented approach starts by randomly generating the size parameters of the meta-atom, and it iteratively obtains the optimized design of the dual narrow band terahertz metamaterial perfect absorber. The quality factor for the two near unity-absorption peaks are 23.8 at 0.5 THz and 60.3 at 0.7 THz, respectively. The device was fabricated using the surface and bulk-micromachining processes, and the measured absorption spectra agrees well with the simulated results. Not limited to this proof-of-concept demonstration, this methodology can be applied to all metamaterial-based photonic systems achieving efficient forward optimization design.

A multiband perfect metamaterial absorber based on phase change material for switching and biosensing applications

In this article, a GST-based metamaterial three-band absorber in the terahertz region with switching and biosensing capabilities, was investigated. The proposed absorber exhibited a high absorption rate of 99% at three different resonance frequencies of 2.49 THz, 7.557 THz, and 9.13 THz. Additionally, the absorber demonstrated switching capability due to the amorphous and crystalline states of the GST phase change material. Its sensitivity to changes in the refractive indices of the test environment was evaluated, and its performance in detecting hemoglobin was studied. The proposed absorber showed a sensitivity of 2061.5 GHz/RIU, 2045 GHz/RIU, and 2041 GHz/RIU in the first to third resonance frequencies. Finally, to validate the proposed structure, an equivalent circuit model was proposed, the results of which showed good agreement with the results of simulation and impedance analysis.

Compatible camouflage for dual-band guided-laser radar and infrared via a metamaterial perfect absorber.

Laser-guided detector and infrared detection have attracted increasing attention in a wide range of research fields, including multispectral detection, radiative cooling, and thermal management. Previously reported absorbers presented shortcomings of lacking either tunability or compatibility. In this study, a metamaterial perfect absorber based on a Helmholtz resonator and fractal structure is proposed, which realizes tunable perfect absorptivity (α 1.06μ m >0.99,α 10.6μ m >0.99) of guided-laser radar dual operating bands (1.06 µm and 10.6 µm) and a low infrared average emissivity (ε¯3-5μ m =0.03,ε¯8-14μ m =0.31) in two atmospheric windows for compatible camouflage. The proposed perfect absorber provides a dynamically tunable absorptivity without structural changes and can be applied to optical communication, military stealth or protection, and electromagnetic detection.

Dumbbell shaped structure loaded modified circular ring resonator based perfect metamaterial absorber for S, X and Ku band microwave sensing applications

In this paper, a new metamaterial absorber (MMA) is presented that exhibits peak absorptions at 3.26 GHz, 11.6 GHz, and 17.13 GHz within S, X, and Ku bands. The unit cell of the proposed MMA is constructed on an FR4 substrate having an electrical dimension of 0.144λ × 0.144λ, where wavelength, λ is calculated at the lowest absorption frequency. The unique structural design of the unit cell consists of two concentric copper rings with which dumbbell-shaped structures are attached. The rotating symmetrical structural design of this MMA provides around 93.8%, 96.47%, and 99.95% peak absorptance in the mentioned frequencies, which is invariable with the change of incident angle as well as polarization angle. The metamaterial properties of the proposed absorber are studied along with the surface current analysis. The MMA shows single negative behaviour and it also exhibits high-quality factors (Q factor) of 21.73, 41.42, and 51.90 at maximum absorptance frequencies. The MMA is analysed by it's equivalent circuit to understand the resonance phenomenon, which is verified through simulation in Advanced Design Systems (ADS) software. The testing is done on the developed prototype of the proposed MMA. Measurement results are in close proximity to the simulation results. Due to its high Q factor, high EMR, and insensitivity to polarization and angle of incidence, it can be utilized as a part of miniaturized microwave device. In addition, the proposed MMA can exhibit high sensing performance and flexibility to differentiate different oils in S, X, and Ku bands.

Metamaterial Engineering for Superior HgTe cQD Photodetector Performance

AbstractHighly responsive, low noise, and inexpensive photodetectors that operate in the mid‐infrared (MIR) wavelength regime are in high demand for applications ranging from fundamental science to large scale industries. However, simultaneously achieving all this in one device architecture is very challenging. In this work, mercury telluride (HgTe) colloidal quantum dot (cQD) based photodetectors are systematically improved by the introduction of new metamaterial designs. The new designs are found by utilizing simulations. Thereby the structures are optimized to increase the responsivity and simultaneously decrease the noise spectral current density. This is achieved by focusing on improving the photogenerated charge carrier collection efficiency while reducing the active material volume without altering the near unity absorption. A standard metamaterial perfect absorber architecture based on disc resonators is used as a starting point for the optimization process. By optimizing the carrier extraction through contact engineering, resulting in a narrow slot metamaterial, an overall ≈13‐fold responsivity and ≈345‐fold detectivity increase is achieved. The final metamaterial design reaches a responsivity of 16.2 A W−1 and detectivity of 6×108 Jones at a wavelength of 2710 nm. The analysis therefore provides a route to improve the responsivity and noise characteristics of mid‐infrared photodetectors based on cost‐efficient colloidal quantum dots.

Two split rings resonator-based perfect metamaterial absorbers with the incident and polarization angle independent for sensing applications

The perfect metamaterial absorber (PMA) optimized for high-performance absorbers to find the multiple sensing application. The structural composition of the PMA consists of two split ring resonators with six split gaps configured in an exhibit symmetry of rotation. The fundamental component of the design has three distinct layers: (1) the top and bottom layers, composed of a metallic substance with copper dielectric substrate with a thickness of 0.035 mm that exhibits lossy metal; (2) the middle layer, made of a lossy dielectric material referred to as Rogers RT5870 dielectric substrate with a thickness of 1.575 mm. The findings reveal that the absorber achieves a broad absorption spectrum, with simulated results from the CST Microwave Studio simulator indicating absorption peaks at 5.88, 9.20, and 15.88 GHz. whereas the strong absorbance is 99.91, 99.99, and 99.97 % with a good quality factor (Q) 29.40, 9.20, 13.23, respectively. The structural dimensions (7 × 7 mm2) are designed to deliver remarkable performance. The tri-band PMA exhibits polarization independent at various angles, including 0, 45, 90, 135, and 180° for both transverse magnetic (TM) and transverse electric (TE) modes. It has excellent absorption capabilities across multiple angles of incidence from 0 to 80°, including the whole operational spectrum. A comparative investigation of the circuit indicates the enhanced performance of the PMA, demonstrating its potential for exceptional functionality inside the advanced design system (ADS) software. Furthermore, the structures under consideration, which were simulated using the High-Frequency Structure Simulator (HFSS), demonstrate a strong agreement with the highest level of absorption seen at each resonance peak in the CST simulation outcomes. This paper introduces an alternative protocol, expressed in terms of the TE and TM modes, for use with the restricted symmetric structure to find multiple sensing application. The proposed study highlights the exceptional properties of PMA provides several practical advantages, including its high absorption capacity, in multiple sensing application, insensitivity to incident and polarization angles, satellite technology, raw satellite feeds, and radars owing to these performance features.

Highly sensitive refractive index sensing with a dual-band optically transparent ITO-based perfect metamaterial absorber for biomedical applications

In this paper, a dual-band optically transparent square-shaped perfect metamaterial absorber operating in the frequency range from 2 to 4 terahertz (THz) is proposed. The structure consists of an indium tin oxide (ITO)-based split ring resonator (SRR) structure with additional splits and rectangular inner strips to form the top layer over the lead glass substrate. Perfect absorption is attained in the frequencies of 2.089 and 3.892 THz with absorbances of 99.99% and 99.98% in TE polarization mode, respectively. Perfect absorption is also achieved in TM polarization mode at 2.23 THz. Broadband absorption is found in TM polarization mode with full width half maximum (FWHM) of 1.1742. The proposed structure has one polarization-insensitive band in TE polarization mode. Absorbance is greater than 80% and 90% in the successive absorption peaks even at 60° and 75° of incidence, respectively. The resonance frequency is sensitive to the refractive index of the medium. As a result, the proposed metamaterial structure may be implemented as a refractive index (RI) sensor with a high sensitivity of 1109 GHz/RIU and 1954 GHz/RIU in both absorption bands for a refractive index range of 1.34 to 1.40. It's interesting to note that the refractive index of most biological samples ranges from 1.3 to 1.39. The figure of merit (FOM) of the proposed sensor can reach as high as 10 and 14 for the 1st and 2nd frequency bands. As a result, the proposed sensor has a high sensitivity and can be employed in medical applications. Potential applications of the proposed absorber include imaging, biomedical sensing, etc.

Polarization-Angle-Insensitive Dual-Band Perfect Metamaterial Absorbers in the Visible Region: A Theoretical Study

Metamaterial absorbers have been studied extensively due to their potential applications in the field of photonics. In this paper, we propose a simulation study of a polarization-angle-insensitive dual-band perfect metamaterial absorber with absorption peaks at 654 and 781 nm, respectively. By adjusting the structure parameters, dielectric thickness, and refractive index, the obtained absorber has high scalability in the visible wavelength region. To further understand the performance of the cross-structure absorber, analysis of its electric and magnetic field distribution shows that it produces two resonance modes leading to different absorption properties. In addition, the position and intensity of the absorption peaks were found to be unchanged with increasing incident polarization angle, indicating that the absorber is insensitive to the polarization of the incident light. The absorber has great flexibility and has good application potential in sensing and detection.

Design of metamaterial perfect absorbers in the long-wave infrared region.

We designed a narrow-band metamaterial absorber (NMA) and an ultra-broadband metamaterial perfect absorber (UMPA) based on the impedance matching theory. The narrow-band metamaterial absorber mainly consists of Si3N4 cylinders with Si3N4 and Ti substrates. Numerical analysis shows that the absorption peak of the NMA is about 99.9% and the absorption bandwidth with more than 90% absorption is about 4.8 μm (9.5-14.3 μm). To further extend the absorption bandwidth, an ultra-broadband absorber was designed by integrating a Ti hyperbolic rectangle into the Si3N4 cylinder of the NMA. Numerical analysis shows that the absorption bandwidth of the UMPA is up to 10 μm (7-17 μm) with an average absorption rate of 96.6%. The designed UMPA has polarization insensitive properties with wide-angle absorption characteristics, and the average absorption can reach 85% and 76% in transverse magnetic (TM) and transverse electric (TE) modes, respectively, at 60° oblique incidence. The high absorption and wide band are mainly dominated by localized surface plasmon resonance, Fabry-Perot resonance and inter-resonance interactions. The designed absorber achieves excellent absorption in the long infrared wavelength band, which has potential applications in energy absorption, infrared sensing and other fields.

Tunable asymmetric square split ring resonator based triple band metamaterial absorber for wireless communication system

This article presents a triple band square split ring with double circular split ring resonator incident angle-insensitive perfect metamaterial absorber. The MMA unit cell was manufactured using a FR4 substrate that had dimensions of 8 mm by 8 mm. With the flexibility of on-design adjusting of the highest absorption frequencies, the suggested MA displays peak absorption of 99.67 %, 99.85 %, and 99.97 % at 2.52 GHz, 6.99 GHz, and 9.28 GHz, correspondingly. The tuning metallic two circular split rings and square split ring resonator provide the possibility of frequency modification throughout three distinct frequency ranges: the first frequency range extends from 2.45 GHz to 2.53 GHz, the second frequency range extends from 6.91 GHz to 7 GHz, and the third frequency range extends from 8.85 GHz to 10.32 GHz. Furthermore, the suggested MA displays near-zero absorption at an oblique incidence angle of up to 45° for both the TE as well as TM modes. The unit cell demonstrates single negative properties, such as an effective medium ratio (EMR) of 14.88 and a quality factor (Q factor) that is more than 30 for both the TM mode as well as the TE mode. An equivalent circuit successfully demonstrated its performance capability, which indicated that it would create an MMA of good quality when using ADS software. A comparison between the measured results of the suggested MMA and the simulated one reveals that there is a significant amount of a similarity between both of them. Because of its easy design within small dimension, wide angular stability, strong absorption, good EMR, and flexibility to frequency tuning is suitable for a wide range of wireless communication system, especially satellite applications like electromagnetic interference reduction, radar systems, imaging, and stealth technology.

Metamaterial Perfect Absorbers for Controlling Bandwidth: Single-Peak/Multiple-Peaks/Tailored-Band/Broadband

Metamaterial absorbers have garnered significant interest due to their unique electromagnetic properties, which facilitate the efficient absorption of electromagnetic radiation in a specific frequency range or multiple frequency ranges. The metamaterial absorbers are designed based on artificially engineered structures that enable tailored absorption properties. These structures might include multiple resonances or incorporate electrical resistive components to achieve broadband absorption. This review paper provides a comprehensive analysis of the progress made in the field of the bandwidth of metamaterial absorbers, encompassing the underlying design principles, key performance characteristics, diverse applications, and perspectives for further research. The paper draws to a conclusion by outlining the potential future directions for further advancements in this exciting area of research, and highlighting the challenges that need to be addressed for the widespread adoption of metamaterial absorbers.

Wide-angle and polarization-insensitive perfect metamaterial absorber

We propose a cross-shaped resonator design of a metamaterial (MTM) absorber that shows a 98% average absorbance in the range of 400–1100[Formula: see text]nm. This design consists of three layers: a tungsten-based cross-shaped on the top, silicon dioxide (SiO2) in the middle layer, and a tungsten layer at the bottom. The finite integration technique (FIT) method is used to simulate the metamaterial absorber’s performance. We have observed the absorber’s performance on the different thicknesses of a dielectric layer. We have presented the absorption spectrum for transverse electric (TE) and transverse magnetic (TM) modes for different polarization angles (0°–90°) and incident angles (0°–60°). Additionally, we have investigated the short-circuit current density for different dielectric layer thicknesses and different incidence angles. This is theoretically analogous to parametric studies. The universal AM 1.5 solar spectrum properties have been used to investigate the feasibility of the proposed MTM absorber as a solar cell. The proposed MTM has many potential uses, including for solar cells.

Rotational symmetric solar system shaped triple band perfect metamaterial absorber for S-, C-, and X-band application

This article offers a metamaterial absorber of solar system shaped design for S-, C-, and X-band using a simple and symmetric structure. This innovative structure consists of two split ring resonator (SRRs) and two circular shape metal strips with a metal disc in the center. The ground metallic layer and upper patches are disjoint by flame retardant dielectric FR-4 (lossy) material of thickness 1.6 mm. Copper (annealed) of depth 0.035 mm is used for the all patches as well as the ground layer. The electrical dimension of the unit cell is 0.1006 λ × 0.1006λ which is calculated at the lower frequency 3.02 GHz. Computer simulation technique (CST) microwave studio is used to derive the numerical results. The simulation result yields three resonance peaks at 3.02, 5.71 and 8.36 GHz with the absorption 99.86%, 97.58% and 97.46%, respectively. The electric field, magnetic field and the surface current distribution are studied to comprehend the absorption mechanism. The reflection coefficient (S11) is also investigated by advanced design system (ADS) electrical equivalent circuit. This unique design of metamaterial absorber (MMA) unit cell is finalized through some parametric studies. The simulated results are also validated by ADS with electrical equivalent circuit and different array orientation. Unit cell, 1 × 2, 2 × 2 and 4 × 4 array of the unit cell are fabricated for measurement purposes. The measurement is carried out with the help of programmable network access (PNA) of Agilent N5227 with waveguide ports. The S-, C-, and X-band are mainly used for satellite communication and radar system. S-band is used for the shipping, aviation and space industries for its efficiency as a conduit for supplying vital real-time data whereas, C band is used for many wireless communication like satellite transmissions, Wi-Fi devices, mobile communication and weather forecasting system. X band is a radar sub-band which is utilized in civil, military, weather monitoring, air traffic control, maritime vessel traffic control, defense tracking.

Multiband terahertz metamaterial perfect absorber for microorganisms detection

We report a multi-resonant terahertz (THz) metamaterial perfect absorber (MPA)-based biosensor in the working frequency range of 0 - 3.8 THz for sensing of microorganisms (such as fungi, yeast) and wheat pesticides. Nearly 100% absorption is realized at f_1= 1.7THz, f_2= 2.8THz, f_3=3.2THz, and f_4=3.5THz. We designed our THz MPA sensor making resonators’ gap area compatible with the microorganisms’ size. To obtain optimum performance of the MPA, a mapping of amplitudes and shifts in the absorption resonance peaks with different structural parameters of the resonators is carried out. A very high-frequency shift is obtained for microorganisms such as Penicillium chrysogenum (fungi), yeast, and pesticides (Imidacloprid, N, N-Diethyldithiocarbamate sodium salt trihydrate, Daminozide, N, N-Diethyldithiocarbamate sodium salt hydrate, and Dicofol). An equivalent circuit model using Advance Design System (ADS) software is developed. The calculated results through the model show similar trends as obtained in the simulations using CST. Investigations of the effect of incidence angle of THz wave on the absorption spectra of the MPA are also carried out. It is found that incidence angle does not impact the stability of the lower resonance absorption peak (1.79THz). Due to the wide working frequency range, the proposed sensor is extremely suitable for the detection of all range of pesticides because their specific absorption fingerprint lies in the frequency range of 0–3.8THz. We believe that our sensor could be a potential detection tool for detecting pesticide residues in agriculture and food products. The THz MPA-based biosensor is capable of detecting a very small change in the effective dielectric constant of the MPA environment. Therefore, it can also offer huge opportunities in label-free biosensing for future biomedical applications.

Polarization-independent and all-optically modulated multiband metamaterial coherent perfect absorber

A polarization-independent, all-optically modulated multiband metamaterial coherent perfect absorber (CPA) is proposed. Numerical simulation results reveal that the absorber can be controlled over a wide range of amplitudes by changing the phase difference of two incident light beams. The all-optical modulation can be extended to telecom wavelengths, allowing for simultaneous modulation of absorption at 1310 nm and 1550 nm. In addition, switchable logical gate states can be achieved at the dip between absorption peaks. The proposed absorber utilizes bound states in the continuum (BIC) mode to realize another absorption band, expanding the application range and enhancing its flexibility. The results suggest that the proposed absorber has a promising modulated optical response, with potential applications in developing optical switches, smart multi-band absorbers, telecom devices and so on.

Polarization-insensitive magnetically tunable perfect absorber for refractive index sensing applications

In this paper, a polarization-insensitive magnetic tunable perfect metamaterial absorber is analyzed which shows its functionality as a refractive index (RI) sensor. The unit cell structure of reported absorber consists of a cross-shaped Indium Arsenide (InAs) array over aluminum ground plane and has dimensions less than [Formula: see text] with thickness of 7.5[Formula: see text][Formula: see text] and periodicity of 9[Formula: see text][Formula: see text] making it an ultra-thin absorber. The proposed absorber provides an average absorption of 99.99% on the implementation of magnetic field (B) at 0.4[Formula: see text]T. The resonance frequency and corresponding absorption rates can be controlled by varying the magnetic field from [Formula: see text]–0.4[Formula: see text]T which provides high absorption as well as shift in the frequency spectrum by 0.3[Formula: see text]THz/T. Additionally, parametric analysis has also been done to confirm the selection of the optimum value of the designed parameters of the structure. Furthermore, simulation results reveal that the proposed structure is very sensitive to the change of RI values in the surroundings thus, the proposed structure can be employed as a RI sensor high sensitivity of 1.083[Formula: see text]THz/RIU over the range of 1–1.6[Formula: see text]RI. In addition, the result shows that the sensor can detect different chemical compounds such as ethanol, gasoline, paraffin, sodium chloride, carbon disulfide with an average sensitivity of 0.925[Formula: see text]THz/RIU. Thus, the proposed absorber with obtained sensitivity can be utilized as a biochemical sensor, making it one of the best contenders for chemical industry uses in diagnosis of different hazardous chemicals as well as finding its applicability in biomedical uses.

Triple band frequency tunable polarization insensitive metamaterial absorber for WLAN and 5G applications

A triple band metamaterial absorber (MMA) has been demonstrated in this paper that is developed on an FR4 substrate targeting WLAN and 5G frequencies. The resonating patch contains three modified concentric copper rings having overall unit cell dimensions of 0.16λ0 × 0.16λ0 × 0.0128λ0, where the wavelength, λ0 is for 2.4 GHz. The MMA exhibits 99.3%, 95.68%, and 99.5% peak absorption at 2.4, 3.5, and 5.85 GHz, respectively. Length variation of inwardly extended metallic stubs attached to the innermost ring provides frequency tuning flexibility for peak absorption within 5.67 GHz–5.98 GHz. The absorption process of the MMA is analyzed through the distribution of surface current. The MMA exhibits incident and polarization angle insensitive behaviour up to 60° for both TE and TM modes with near zero polarization conversion ratio. The resonance characteristics are justified through equivalent circuit modelling with validation by Advanced Design software (ADS). The measured absorption indicates a close resemblance with the simulation. Moreover, a good effective medium ratio of 6.25 shows the compactness of MMA. Due to its compact structure, incident, and polarization angle insensitivity, and near unity absorption at application-specific frequencies, this perfect MMA can be suitable for WLAN and 5G applications, especially for microwave shielding and sensing.

Design and analysis of quad-band polarization-insensitive infrared perfect metamaterial absorber with a wide-incident angle

There is a pressing demand to design simple absorber structures that support optimal absorption in multi-band to meet different applications. In this work, a novel quad-band infrared perfect metamaterial absorber (QPMA) is proposed and numerically investigated. The structure of the QPMA is composed of coaxial multi-layer dielectric (SiO2) disks of circular shape with different diameters where each disk is surrounded by a gold ring. All disks are placed on a SiO2 dielectric spacer and an impermeable gold ground layer. Simulation results reveal that the proposed absorber has four absorption peaks around wavelengths of 1064 nm, 1550 nm, 2080 nm, and 3000 nm. Since these wavelengths correspond to commercially available laser sources, the structure under investigation can be used in different applications such as laser stealth, infrared photodetection, and medical applications. Additionally, the QPMA structure enjoys a good absorption performance for a wide range of incident angles for both TE and TM waves. It achieves absorption greater than 85% at incident angles up to 40° at 1064 nm, and absorption greater than 90% for the other bands at incident angles up to 50°. Moreover, due to the symmetrical shape of the structure, the absorption is insensitive to wave polarization changes.

Optimizing the design of broadband solar metamaterial absorbers based on titanium nitride nanorings [Invited]

We propose a design rule for broadband metamaterial absorbers and investigate their plasmonic properties under solar irradiation. The metamaterials consist of periodic arrays of titanium nitride (TiN) rings placed on an antireflective MgF2 dielectric film on a TiN bottom layer. We simulate the absorption of our metamaterials and find the dependence of the optical spectrum on structural parameters. From this, we propose a simple rule to design the nanostructures with an average spectral absorptivity greater than 95% over the solar spectrum from 200 to 3000 nm. Particularly, we introduce, for the first time, metamaterial perfect absorbers that can be designed using two-layer structures instead of higher-layer structures as conventional and sandwich designs. Our study would pave the way for great potential applications in the fields of solar energy harvesters and photo-to-thermal converters.

Dual-band complementary metamaterial perfect absorber for multispectral molecular sensing.

Metamaterial perfect absorbers (MPAs) show great potential in achieving exceptional sensing performance, particularly in the realm of surface-enhanced infrared absorption (SEIRA) spectroscopy. To this aim, it is highly desirable for the localized hotspots to be readily exposed and accessible to analyte with strong mode confinement to enhance absorption. Here, we propose a quasi-three-dimensional MPA based on cross-shaped coupled complementary plasmonic arrays for highly sensitive refractive index sensing and molecular vibrational sensing. Dual-band perfect absorption can be approached with the two plasmonic resonances corresponding to the electric dipole-like mode of cross antenna array and the magnetic dipole-like mode of cross hole array, respectively. Large portions of the electric field of the hotspots are exposed and concentrated in the gap between the elevated cross antenna and its complementary structure on the substrate, leading to improved sensing sensitivities. An ultrathin polymethyl methacrylate (PMMA) film induces a significant redshift of the magnetic dipole-like mode with an 11.8 nm resonance shift per each nanometer polymer thickness. The value is comparable to the reported sensitivity of single molecule layer sensors. Additionally, the simultaneous detection of the C = O and C-H vibrations of PMMA molecules is enabled with the two plasmonic resonances adjusted by changing the lengths of the two cross branches. Remarkably, the observed mode splitting and anti-crossing behavior imply the strong interaction between plasmonic resonance and molecular vibration. Our dual-band MPA based on coupled complementary plasmonic arrays opens a new avenue for developing highly sensitive sensors for the detection of refractive index and multispectral molecular vibrations.