High-performance Refractive Index Sensor Research Articles

Graphene oxide based plasmonic nano-cavity sensor for high-performance refractive index sensing

Abstract In this work, a nano-cavity based metal-insulator-metal structure is proposed which can be used as a high-performance refractive index sensor. The analysis of its sensing capabilities is done by determining the transmission characteristics of light through the insulating air channel between the metal layer. The loss in transmission in this channel is indicative of light leaking out of it and portion of it getting coupled to nano-cavities considered in the metal layers on both sides of the air channel. The analyte, whose refractive index is to be sensed, is kept in these nano-cavities. The basic structure is modified by introducing graphene oxide (GO) on the inner wall of the nano-cavity, which further improves the confinement of light in the nano-cavities. It is also shown that increasing the number of nano-cavity duos enhances the transmission loss through the waveguide and as a result the light energy confinement in the cavity increases. Calculated values of sensitivities and Figure of Merit of the proposed sensor structure are much higher than similar works done previously. The uniqueness of the work is two-fold; namely use of graphene oxide as an inner layer of the nano-cavity improves the sensitivity of the sensor and secondly calculating the waveguide transmission to indirectly determine the confinement of light energy in nano-cavity simplifies the analysis of the performance of the proposed sensor. The structure is simple and can be easily fabricated using a standard fabrication process.

Dual-narrowband terahertz metamaterial absorber based on all-metal vertical ring array for enhanced sensing application

In this paper, a novel design of a dual-narrowband metamaterial absorber (MMA) was proposed for using as a high-performance refractive index (RI) sensor in the terahertz (THz) region. The proposed MMA is based on a vertical-ring-shaped (VRS) structure gold film array. Through numerical simulation, it was found that the MMA can achieve high absorption levels of 99.8% and 94.6% at 1.723 THz and 2.457 THz, respectively, which are consistent with the values obtained using coupling mode theory (CMT). The MMA also exhibits high Q-factor values of about 27.35 and 102.38, respectively, which are close to the CMT values of 29.94 and 98.34. The dual-band strong absorption of the MMA is attributed to the guided modes of the critical coupling resonance, and the absorption properties can be adjusted by changing the geometrical parameters of the unit-cell structure. The proposed MMA has a narrowband and a higher Q-factor, making it suitable for RI sensing, with a sensitivity of about 1.66 and 1.88 THz RIU−1, and a figure-of-merit (FOM) of about 259.4 and 659.7 RIU−1, respectively. These findings open up new opportunities for the development of highly efficient MMAs, which have potential applications in biochemical sensing and detection in the THz region.

Gas concentration and refractive index sensor based on plasmonic induced absorption in metal-insulator-metal waveguide coupled with arc resonators structure

In this paper, the plasmonic induced absorption (PIA) effect is numerically studied in a plasmonic metal-insulator-metal (MIM) waveguide coupled with disk and arc-shaped resonators. The PIA spectrum characteristics and magnetic field distributions are investigated by the Finite difference-time domain method (FDTD) method, the PIA effect originated from the coupling of two resonance modes excited by the disk resonator and the arc-shaped resonator. The coupling mode theory (CMT) is used to fit the PIA transmission spectrum, and the calculated result fits well with the simulated spectrum. A double PIA spectrum can be observed by introducing another arc-shaped resonator both on the same or the opposite side. Three different structures are designed to achieve the PIA effect, and we found the PIA response can be easily tuned by altering the structure’s parameters. Three structures are designed and compared, the PIA spectra exhibit high refractive index (RI) sensing with maximum sensitivity of 867.2nmRIU−1. Besides, the proposed structure can also be used as a gas concentration (GC) sensor when the polyhexamethylene biguanide (PHMB) is introduced, a maximum sensitivity of 142.1 pm/ppm is achieved for the proposed structure II, the maximum figure of merit (FOM) and Q value are 57.8 and 65.9, respectively. Therefore, the results represented in this paper will be beneficial in the fields of high-performance refractive index and gas sensors.

Performance analysis and optimization of high Q-factor toroidal resonance refractive index sensor based on all-dielectric metasurface

Sensing is a crucial step to provide information for biology and chemistry. The introduction of a new method with high sensitivity, robustness and low cost has been a research hotspot recently. In this paper, we propose a split ring metasurface composed of silicon nanorods, which shows ultra-high local field enhancement in the near infrared band. Further, the enhanced toroidal dipole is confirmed by multipole decomposition and surface current distribution. Then, the parameter adjustment and sensing performance are analyzed and calculated, and the obtained sensitivity and figure of merit (FOM) are 430 nm/RIU and 1720 RIU−1 respectively. In order to improve the sensing performance, three different substrate etching schemes are proposed, in which the maximum sensitivity and FOM values are 500.75 nm/RIU and 3013.33 RIU−1 respectively. Lastly, the effects of material loss, substrate and array effect on Fano resonance are analyzed. The proposed scheme may provide a new idea for the design and optimization of high-performance refractive index sensor.

Broadband differential interference in a waveguide with a gradient refractive index distribution

The paper presents a model of a planar broadband differential waveguide interferometer with a gradient refractive index distribution. Its response to the change in the refractive index of the waveguide cover layer is presented. The analysis was performed for the wavelength range from 0.5um to 0.7um. The orthogonal TE0 and TM0 modes propagating in this wavelength range are considered. The influence of the coverage refractive index change on the output characteristics of the system is shown. Full Text: PDF ReferencesP. Kozma, F. Kehl, E.Ehrentreich-Forster, C. Stamm and F.F. Bier, "Integrated planar optical waveguide interferometer biosensors: A comparative review", Biosens. Bioelectron. 58, 287 (2014), CrossRef M. Kitsara, K. Misiakos, I. Raptis, and E. Makarona, "Integrated optical frequency-resolved Mach-Zehnder interferometers for label-free affinity sensing", Opt. Express 18, 8193 (2010). CrossRef K. Misiakos, I. Raptis, A. Salapatas, E. Makarona, A. Bostials, et al., "Broad-band Mach-Zehnder interferometers as high performance refractive index sensors: Theory and monolithic implementation", Opt. Express 22, 8856 (2014). CrossRef K. Misiakos, I. Raptis, E. Makarona, A. Botsialas, A. Salapatas, et al, "All-silicon monolithic Mach-Zehnder interferometer as a refractive index and bio-chemical sensor", Opt. Express 22, 26803 (2014) CrossRef K. Misiakos, E. Makarona, M. Hoekman, R. Fyrogenis, K. Tukkiniemi, et al., "All-Silicon Spectrally Resolved Interferometric Circuit for Multiplexed Diagnostics: A Monolithic Lab-on-a-Chip Integrating All Active and Passive Components", ACS Photonics 6, 1694 (2019). CrossRef E. Makarona, A. Salapatas, I. Raptis, P. Petrou, S. Kakabakos, et al., "Broadband Young interferometry for simultaneous dual polarization bioanalytics", J Opt Soc Am B 34, 1691 (2017). CrossRef K. Gut, "Broad-band difference interferometer as a refractive index sensor", Opt. Express 25, 3111 (2017), CrossRef K. Gut, "Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides", Nanomaterials 9, 729 (2019), CrossRef T. Pustelny, J. Ignac-Nowacka and Z. Opilski, "Optical investigations on layered metalphthalocyanine nanostructures affected by NO2 applying the surface plasmon resonance method", Opt. Appl. 34, 563 (2004). CrossRef W. Lukosz, Sensor Actuat. B-Chem. "Integrated optical chemical and direct biochemical sensors", 29, 37 (1995). CrossRef Z. Qi, S. Xia and N. Matsuda, "Spectropolarimetric interferometer based on single-mode glass waveguides", Opt. Express, 16, 2245 (2008). CrossRef K. Gut, A. Zakrzewski, T. Pustelny, "Sensitivity of Polarimetric Waveguide Interferometer for Different Wavelengths", Acta Phys. Pol. 118, 1140 (2010). CrossRef J.E. Broquin, S. Honkanen, "Integrated Photonics on Glass: A Review of the Ion-Exchange Technology Achievements", Appl.Sci. 11, 4472 (2021). CrossRef G.C. Righini, J. Linares, "Active and Quantum Integrated Photonic Elements by Ion Exchange in Glass", Appl.Sci. 11, 5222 (2021). CrossRef

Polarization multiplexed electromagnetically induced transparency metasurface based on VO2 with high-performance sensing application

A vanadium dioxide (VO2) based dielectric metasurface is proposed to realize polarization multiplexed electromagnetically induced transparency (EIT) effect with tunability. In the near-infrared regime, distinct transparency windows with high transmission intensity and quality factor (Q-factor) can be observed under the excitation of two orthogonal polarized lights. By changing the conductivity of VO2, the EIT peak intensity and the group delay of the incident light can be manipulated dynamically. Meanwhile, the narrow transparency window is extremely sensitive to the change of the surrounding refractive index, and the proposed metasurface exhibits high sensitivity and figure of merits in both x- and y-polarization conditions. Therefore, the proposed dielectric metasurface based on VO2 provides a new method for dynamically controlled EIT effects in the near-infrared region and inspires potential applications in optical modulations, tunable slow light devices, and high-performance refractive index sensors, etc.

High-performance refractive index sensor by nano-cylindrical surface structure

In this work, a two-dimensional grating structure based on the metal assisted guided-mode resonance (MAGMR) effect is proposed, which can be used for near infrared band sensing in an aqueous environment. Following optimization by the finite-difference time-domain method, the structure is able to support MAGMR well, and has an excellent reflection dip. The electromagnetic field shows that the structure not only interacts well with the sensing medium but also has a large penetration depth. Results at different refractive indices of the sensing medium confirm the high sensing performance of the proposed MAGMR sensor, which achieves a sensitivity of 852 nm/RIU. Meanwhile, the sensor has a figure of merit up to 4813 RIU−1 (55 times typical GMR sensors) because of the full width at half maximum is only 0.177 nm. Furthermore, the shape and parameters of the MAGMR sensor have been analyzed in detail in order to gain a comprehensive understanding of its performance. This MAGMR sensor is promising for future applications in biomedicine, chemical measurements and environmental monitoring due to its polarization-independent, non-specific angle of incidence, high penetration depth and high sensing performance.

A High-Performance Refractive Index Sensor Based on Hybrid Resonance Modes in a Square Nanocavity Coupled with Metal–Insulator–Metal Plasmonic Waveguide

A High-Performance Refractive Index Sensor Based on Hybrid Resonance Modes in a Square Nanocavity Coupled with Metal–Insulator–Metal Plasmonic Waveguide

Toward high-performance refractive index sensor using single Au nanoplate-on-mirror nanocavity.

Refractive index sensors based on the localized surface plasmon resonance (LSPR) have emerged as powerful tools in various chemosensing and biosensing applications. However, owing to their limited decay length and strong radiation damping, LSPR sensors always suffer from low sensitivity and small figure of merit (FOM). Here, we fabricate a plasmonic nanocavity sensor consisting of a hexagonal Au nanoplate positioned over an ultrasmooth Au film. The strong coupling between the nanoplate and the lower metal film allows for the formation of a plasmonic gap mode that enhances the interaction of the local field with the ambient glycerol solution to increase the sensitivity. Meanwhile, the plasmonic gap mode has a trait of an antiphase charge oscillation in the gap region, imparting a strongly reduced radiative damping and a subsequently promoted FOM. The performance of our proposed refractive index sensor is further boosted by decreasing the gap size of the nanocavity, yielding an outstanding FOM of 11.2 RIU-1 that is the highest yet reported for LSPR sensing in a single nanostructure.

A MIM Waveguide Structure of a High-Performance Refractive Index and Temperature Sensor Based on Fano Resonance

A plasmonic refractive index nanosensor structure consisting of a metal-insulator-metal (MIM) waveguide with two symmetrical rectangle baffles coupled with a connected-concentric-double rings resonator (CCDRR) is presented. In this study, its transmission characteristics were investigated using the finite element method (FEM). The consequences, studied via simulation, revealed that the transmission spectrum of the system presents a sharp asymmetric Fano profile due to the destructive interference between the wide-band mode of two rectangle baffles on the bus waveguide and the narrow-band mode of the CCDRR. The effects of the geometric parameters of the structure on the transmission characteristics were investigated comprehensively. A sensitivity of 2260 nm/RIU and figure of merit (FOM) of 56.5 were the best levels of performance that the designed structure could achieve. In addition, the system could act as a sensor for use for temperature sensing, with a sensitivity that could reach 1.48 nm/°C. The designed structure advances with technology with new detection positions and has good application prospects in other high-sensitivity nanosensor fields, for example, acting as a biosensor to detect the hemoglobin level in the blood.

Design and Numerical Analysis of Extreme Sensitivity Refractive Index Sensor Based on Cavity Resonance Mode With Strong Electric Field

The use of relatively simple structures to achieve high performance refractive index sensors has always been urgently needed. In this work, we propose a lithography-free sensing platform based on metal-dielectric cavity, the sensitivity of our device can reach 1456700 nm/RIU for solution and 1596700 nm/RIU for solid material, and the FOM can be up to 1234500 /RIU for solution and 1900800 /RIU for solid material, which both are much higher than most sensing methods. This sensor has excellent sensing performance in both TE and TM light, and suitable for integrated microfluidic channels. Our scheme uses a multi-layers structure with a 10 nm gold film sandwiched between prism and analyte, and shows a great potential for low-cost sensing with high performance.

High-performance refractive index sensor for oil derivatives based on MWCNT photonic crystal microcavity

In this paper, we propose a new all-optical sensor based on a two-dimensional (2D) regular array of multi-walled carbon nanotubes (MWCNTs) for the refractive index sensing of oil derivatives, for the first time. The interaction of optical wave with the desirable oil derivatives is enhanced using the slow light effect that makes the group velocity go down. We consider the geometric feature for the proposed sensor structure as a photonic crystal (PhC) with a line defect formed by missing some rows of MWCNT elements. The difference of refractive index △n = 0.1418 between Butanol (C4H10O) and Nitrobenzene (C6H5NO2) host materials results in a wavelength shift of 149 nm, and indicates a sensitivity of 1050 nm/RIU, which can be widely used for the bio/chemical detection and environmental monitoring. To achieve the physical stability of the proposed sensor, MWCNTs are considered to be grown in the AAO (Al2O3) template. By removing one or two rows of the MWCNTs and creating a linear defect within the sensor structure, whereas oil derivatives are injected into the defect area. We have achieved a sensitivity up to 870 nm/RIU. This proposed sensor with un-reactive structure of MWCNTs can be used in environments with high temperature and pressure such as oil refinery industry and other chemical processes industries under wide range of different reaction conditions.

High-Performance Optical Refractive Index Sensor Based on Concave Resonant Grating

High-Performance Optical Refractive Index Sensor Based on Concave Resonant Grating

Dual-band dielectric metamaterial absorber and sensing applications

We present numerically a dual-band dielectric metamaterial absorber where a silica film layer is inserted between the top asymmetric silicon dimer array and the bottom metal substrate. The simulation results show that we can get two resonance peaks (labeled A and B) with near-perfect absorption in the near-infrared regime. Peak A, which is originated from the cavity resonance in the gaps of the dimers, has a full width at half-maximum (FWHM) of 4.8 nm and quality factor of 407. And peak B, which is originated from the destructive interfering of the asymmetric dimers, has an ultra-narrow bandwidth of 0.0014 nm and quality factor of 1.38×106which are much superior to those of the existing metamaterial absorbers. In addition, the simulations also show that the absorption bandwidths can be further narrowed by adjusting the silica layer thickness. Due to the ultra-narrow bandwidths, peaks A and B have the high figure of merits (FOMs) of 51.4 and 6.0×104. Such high FOMs indicate that the proposed dual-band absorber can be applied as a high-performance refractive index sensor.

Model of the planar broadband differential waveguide interferometer as a humidity sensor

The paper presents a model of the planar broadband differential waveguide interferometer. Its response to the change in thickness and refractive index of the waveguide layer due to the change in humidity is presented. The analysis was carried out for the wavelength range from 450 nm to 850 nm. The orthogonal modes TE0 and TM0, which propagate in this wavelength range, are considered. It is shown that by using light near the maximum of the system characteristic, instead of the spectrometer, the total power at the system output can be measured. Full Text: PDF ReferencesM. Kitsara, K. Misiakos, I. Raptis, and E. Makarona, "Integrated optical frequency-resolved Mach-Zehnder interferometers for label-free affinity sensing", Opt. Express 18, 8193 (2010). CrossRef K. Misiakos, I. Raptis, A. Salapatas, E. Makarona, A. Bostials, et al., "Broad-band Mach-Zehnder interferometers as high performance refractive index sensors: Theory and monolithic implementation", Opt. Express 22, 8856 (2014). CrossRef K. Misiakos, I. Raptis, E. Makarona, A. Botsialas, A. Salapatas, et al "All-silicon monolithic Mach-Zehnder interferometer as a refractive index and bio-chemical sensor", Opt. Express 22, 26803 (2014). CrossRef K. Misiakos, E. Makarona, M. Hoekman, R. Fyrogenis, K. Tukkiniemi, et al., "All-Silicon Spectrally Resolved Interferometric Circuit for Multiplexed Diagnostics: A Monolithic Lab-on-a-Chip Integrating All Active and Passive Components", ACS Photonics 6, 1694 (2019). CrossRef E. Makarona, A. Salapatas, I. Raptis, P. Petrou, S. Kakabakos, et al., "Broadband Young interferometry for simultaneous dual polarization bioanalytics", J Opt Soc Am B 34, 1691 (2017). CrossRef K. Gut, "Broad-band difference interferometer as a refractive index sensor", Opt. Express 25, 3111 (2017). CrossRef K. Gut, "Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides", Nanomaterials 9, 729 (2019). CrossRef W. Lukosz, "Integrated optical chemical and direct biochemical sensors", Sensor Actuat. B-Chem. 29, 37 (1995). CrossRef W. Knoll, O. Azzaroni, H. Duran, J. Kunze-Liebhäuser, K. Lau, et al. "Nanoporous thin films in optical waveguide spectroscopy for chemical analytics", Analytical and Bioanalytical Chemistry 412, 3299 (2020). CrossRef A. Bucciarellia, V. Mullonib, D. Maniglio, R.K. Pal, V.K. Yadavalli, at al., "A comparative study of the refractive index of silk protein thin films towards biomaterial based optical devices", Optical Materials 78, 407 (2018). CrossRef V.Prajzler, K. Min, S. Kim, and P. Nekvindova, "The Investigation of the Waveguiding Properties of Silk Fibroin from the Visible to Near-Infrared Spectrum", Materials 11, 112 (2018). CrossRef Q. Li, N. Qi, Y. Peng, Y. Zhange, L.Shi, et al. "Aggregation induced red shift emission of phosphorus doped carbon dots", RSC Advances 7, 178889 (2017). CrossRef P. Giovanni, Z. Yuji, N. Deboki, P. Nereus, D. Kaplan, et al. "The optical properties of regenerated silk fibroin films obtained from different sources", App. Phys. Lett. 111, 103702 (2017). CrossRef M. Procek, Z. Opilski, A. M. Maquenda, X.M. Berbel, S.Aznar-Cervantes et al., "Silk fibroin thin films for optical humidity sensing", Proceedings of SPIE 11204,1120409 (2019). CrossRef https://www.thorlabs.com/thorproduct.cfm?partnumber=M595F2 DirectLink

Model of the broadband interferometric optical biosensor in a planar configuration

The paper presents numerical studies of the model of an optical sensor based on interference of modes in planar one-dimensional step-index configuration, excited by a broadband light source from a selected spectral range. The refractive index variation of measured external surrounding affects the modal properties of multimode waveguide and the spectral field distribution at the output of the structure. The optical system described is designed to the analysis of biological substances. Full Text: PDF ReferencesM. Blahut, "Optical sensor in planar configuration based on multimode interference" Proc. SPIE, 10455, (2017). CrossRef K. Misiakos, et al, "Broad-band Mach-Zehnder interferometers as high performance refractive index sensors: Theory and monolithic implementation", Opt. Express, 22, 8856, (2014). CrossRef K. Gut, "Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides", Nanomaterials, 9, 729 (2019). CrossRef M. Nordstrom, et al, "Single-Mode Waveguides With SU-8 Polymer Core and Cladding for MOEMS Applications", J. Light. Techn., 25, 1284, (2007). CrossRef D. Segelstein, "The complex refractive index of water", M.S. Thesis, University of Missouri, (1981). DirectLink https://www.yokogawa.com/pl/solutions/products-platforms/ DirectLink

Tunable electromagnetic characteristics of suspended nanodisk metasurface

The increasing demand for high-performance optical components in optical integrated systems calls for tunable filter with broadband and narrowband tunability. Here, we propose four designs of tunable metasurface absorber (TMA) composed of suspended nanodisk metasurface with single- and dual-layer Al/SiO2 and Al/LiNbO3 thin-films on Si substrate coated with an Al mirror layer atop, which are denoted as TMA-S1, TMA-S2, TMA-L1, and TMA-L2, respectively. Four devices show the resonant wavelengths with ultrabroad tuning ranges and perfect absorptions. The broadest tuning ranges are 239 nm, 400 nm, 293 nm, and 400 nm, which can be designed to span 60%, 100%, 73% and 100% of visible spectra range for TMA-S1, TMA-S2, TMA-L1 and TMA-L2, respectively. TMA-S2 and TMA-L2 exhibits the characterizations of stronger absorption intensity and narrower bandwidth compared to TMA-S1 and TMA-L1. Furthermore, the absorption resonances of devices are red-shifted by changing ambient refractive index. The corresponding sensitivities are 292.85 nm/RIU, 277.14 nm/RIU, 458.57 nm/RIU and 401.25 nm/RIU for TMA-S1, TMA-L1, TMA-S2 and TMA-L2 respectively. The proposed designs of TMA open an avenue to the possibilities for high-efficiency wavelength-selective devices and high-performance refractive index sensors in the visible spectral range.

Ultra-narrowband dielectric metamaterial absorber with ultra-sparse nanowire grids for sensing applications

Due to their low losses, dielectric metamaterials provide an ideal resolution to construct ultra-narrowband absorbers. To improve the sensing performance, we present numerically a near-infrared ultra-narrowband absorber by putting ultra-sparse dielectric nanowire grids on metal substrate in this paper. The simulation results show that the absorber has an absorption rate larger than 0.99 with full width at half-maximum (FWHM) of 0.38 nm. The simulation field distribution also indicates that the ultra-narrowband absorption is originated from the low loss in the guided-mode resonance. Thanks to the ultra-narrow absorption bandwidths and the electric field mainly distributed out of the ultra-sparse dielectric nanowire grids, our absorber has a high sensitivity S of 1052 nm/RIU and a large figure of merit (FOM) of 2768 which mean that this ultra-narrowband absorber can be applied as a high-performance refractive index sensor.

A high-performance refractive index sensor based on a triangular-lattice photonic crystal with defect and surface modes

The refractive index sensing capabilities of a 2D triangular-lattice photonic crystal (PhC) with defective and surface modes are studied. These are composed of silicon columns arranged in a liquid environment. Through changing the rods’ shape on the PhC’s surface from a circle to an ellipse and optimizing the sizes of two adjacent ellipses, the surface localized mode can be generated. Combining the central defective mode with surface modes, an ultra-small three-working-wavelength PhC refractive index sensor is proposed. The shift of the resonant wavelengths influenced by the slight alteration of the protein’s thickness attached by the special rods is studied, and it is found that a minimum alteration of the protein’s thickness of about 4 nm can be distinguished, and a maximum refractive index sensitivity of 0.516 is obtained. Three kinds of analytes can be detected in real-time and at the same time, which are bounded around the input/output surfaces and the central rods through biological specific binding.

Ultra-Sensitive Refractive Index Sensors Based on Bloch Surface Waves With Transition Metal Dichalcogenides

Bloch surface wave (BSW) sensors are considered to be a great candidate to replace the conventional surface plasmon resonance (SPR) sensors. In this paper, a high performance refractive index sensor based on BSW resonance in the truncated one-dimensional photonic crystal (1DPC) has been theoretically confirmed using transition metal dichalcogenides (TMDCs). The impact of four different two-dimensional TMDCs nanosheets on the sensors are studied, with which the state of art sensitivity of wavelength-interrogation has been achieved. Specifically, with MoSe2, WSe2, MoS2, and WS2 nanosheets, the measured figure of merit (FOM) are 732.1/RIU, 733.0/RIU, 730.5/RIU, and 700.7/RIU, respectively. To our knowledge, this is the best performance achieved so far compared to the existing BSW and SPR sensors. Besides, the impact of the 1DPC period and the number of TMDCs layers were discussed in detail. In addition, at the interface of TiO2 and TMDCs, it is found that the electric intensity is enhanced by nearly 7 times compared to the initial intensity, which also results in an increased evanescent depth in the sensing medium. The high sensitivity sensors proposed in this paper can be applied in the field of biological and chemical sensing.