Maximum Amplitude Sensitivity Research Articles

A novel butterfly-shaped core mode-based asymmetric slotted sensor for ultra-high sensitivity in sucrose concentration detection

In this research, we proposed an asymmetric rectangular slotted biosensor using photonic crystal fiber (PCF), which is subject to surface plasmon resonance (SPR). The proposed sensor utilizes only seven air holes, ensuring better fabrication feasibility and their properties are determined through finite element method (FEM)-based numerical analysis. To simplify the manufacturing process and ensure chemical stability, chemically impermeable gold (Au) strips are employed around the perimeter of the structure as the plasmonic material. With effective structural parameters, the maximum amplitude sensitivity for the proposed sensor is 663.13 RIU−1, the maximum wavelength sensitivity is 204,000 nm/RIU, and the maximum wavelength resolution is 4.90 × 10−7RIU for the y-polarized mode. It also shows a high linearity of 0.9849. For the detection of sucrose content, it has a maximum wavelength sensitivity of 207070.71 nm/RIU and a maximum amplitude sensitivity of 662.80 RIU−1. The newly introduced sensor can detect the refractive index (RI) of various analytes across a broad spectrum, ranging from 1.28 to 1.41. This extensive detection range allows the sensor to precisely measure sucrose concentrations up to 40%. This broad range enables the analysis of various analytes like sucrose, viruses, cancer cells, proteins, and numerous others.

PCF Based Four-Channel SPR Biosensor With Wide Sensing Range.

In this article, we have demonstrated a highly sensitive four-channel photonic crystal fiber (PCF) based surface plasmon resonance (SPR) biosensor which can detect four different analytes simultaneously. To ease practical implementation, four analyte sensing layers and plasmonic materials such as gold (Au) and gold (Au) with Tantalum Pentoxide (Ta2O5) are placed on the exterior of the four arms of the square shaped structure. The sensor's structure consists of only nine circular air holes, making it simple and easy to fabricate using currently available technologies. Finite element method (FEM) based numerical analysis is used to evaluate the sensing performance of the proposed sensor. With optimum structure parameters, the sensor achieves maximum wavelength sensitivity of 11000, 25000, 11000 and 25000 nm/RIU for Channel-1, Channel-2, Channel-3, and Channel-4 respectively. It shows maximum amplitude sensitivity of 803.732, 709.171, 803.827, 709.146 RIU -1 for Channel 1, 2, 3, and 4 respectively. It also shows maximum FOM of 232.55, 352.36, 231.57, 352.36 RIU -1 in Ch-1, Ch-2, Ch-3 and Ch-4 respectively. Moreover, the proposed sensor shows a wide range of refractive index sensing capability from 1.30 to 1.41. Due to multi-analyte detection capability, large sensing range, and excellent sensitivity the proposed sensor unfolds unrivalled capacity of detecting chemicals, carcinogenic agents, biomolecules, and other analytes.

Machine learning-enhanced surface plasmon resonance based photonic crystal fiber sensor

This study introduces what we believe to be a novel photonic crystal fiber sensor utilizing surface plasmon resonance (SPR), incorporating four gold nanowires to enhance sensing capabilities. The research employs machine learning, specifically artificial neural networks (ANN), to predict confinement loss and sensitivity, achieving high accuracy without needing the imaginary part of the effective refractive index. The machine learning technique is applied in three different scenarios, resulting in mean squared errors of 0.084, 0.002, and 0.003, highlighting the reliability of the ANN models in predicting sensor outputs. Additionally, the sensor demonstrates impressive wavelength sensitivities of 2000-18000 nm/RIU (nanometers per refractive index unit) for refractive indices of 1.31-1.4 within the 720-1280 nm wavelength range, and a notable maximum amplitude sensitivity of 889.89 RIU-1. This integration of SPR, photonic crystal fiber, and machine learning not only optimizes sensor performance but also offers an efficient methodology for prediction, showcasing the potential of machine learning in advancing optical sensor design.

Numerical analysis and early detection ofPlasmodium falciparum using a high performanceplasmonic biosensor with an external sensingapproach.

The authors propose a surface plasmon resonance (SPR) sensor based on photonic crystal fibers (PCFs) using three hexagonal ring lattices. The sensor can detect biomolecules with maximum wavelength and amplitude sensitivities of 23,000nm/RIU and 1310.93R I U -1, respectively, in the RI range of 1.32 to 1.42. It can detect infected red blood cells with Plasmodium falciparum for RIs of 1.402, 1.373, 1.395, and 1.383 in various malaria-infected red blood cell stages, including ring phase, trophozoite phase, and schizont phase. Furthermore, the sensor will be able to detect biomolecules such as viruses, proteins, DNA/RNA strands, acetone, ethanol, hexane, isopropanol, hexanol, formic acid, allyl cyanide, and others in its range. With these impressive results and identification capacity, the proposed sensor would benefit the biomaterial field and be appropriate for the early identification of malaria disease.

High-sensitivity dual U-shaped PCF-SPR refractive index sensor for the detection of gas and liquid analytes.

A dual U-shaped photonic crystal fiber (PCF) biochemical sensor based on surface plasmon resonance (SPR) is designed for the simultaneous detection of gas and liquid analytes, and the properties are analyzed by the full vector finite element method (FEM). SPR is excited by placing gold nanowires on the inner surface of the U-shaped device. In this technique, the traditional metal deposition process can be replaced, subsequently reducing the difficulty and complexity of actual production and improving the phase matching between the basic mode and plasmonic modes. To improve the detection properties, the structural parameters of the sensor including the air hole diameter, spacing, gold nanowire diameter, and polishing depth are optimized, and to better evaluate and analyze the sensing properties, the wavelength and amplitude modulation inquiry method is adopted. The results show that the maximum wavelength sensitivity (WS), amplitude sensitivity (AS), minimum resolution (R), and optimal FOM are 35,000nm/RIU, 438.08R I U -1, 2.86×10-6 R I U, and 165.16R I U -1, respectively. In addition, the sensor can detect analyte RIs between 1.00 and 1.36 for gas and liquid analytes simultaneously. Owing to the simple structure, low cost, and ambient-condition monitoring, the sensor has large potential in a myriad of applications including sewage treatment, food safety, humoral regulation, environmental and biological monitoring, and medical diagnosis.

Numerical Study of Early Detection of Tuberculosis Infected with High Sensitivity Plasmonic Sensor

In this work, a photonic crystal fiber based on a plasmonic sensor for the early detection of tuberculosis has been designed with finite element analysis. The component is constructed with a substrate layer made of fused silica material, which is then coated with a thin film of TiO2 layer as an adhesive layer to strongly attach the Au layer with the silica fiber surface. The TiO2 layer has an optimal thickness of 45 nm, while the Au layer has a thickness of 50 nm. The sensor design has a refractive index (RI) detection range from 1.27 RIU to 1.37 RIU, it also shows a maximum wavelength sensitivity (WS), maximum amplitude sensitivity (AS), sensor resolution (SR), and sensor accuracy (SA) of 20,000 nm/RIU (x-polarized) and 17.000 nm/RIU( y-polarized), -211.38 1/RIU (x-polarized) and -211.211 1/RIU (y-polarized), 9.17 x 10−5 RIU (x-polarized) and 1 x 10−4 RIU (y-polarized), and 0.025/nm respectively. Tuberculosis exhibits a normal and infected RI range of 1.343 RIU to 1.351 RIU. Therefore, the proposed sensor design is capable of detecting four types of TB infections with high sensitivity.

A Novel Plasmonic Sensor Based on Dual-Channel D-Shaped Photonic Crystal Fiber for Enhanced Sensitivity in Simultaneous Detection of Different Analytes.

A dual-channel D-shaped photonic crystal fiber (PCF) based plasmonic sensor is proposed in this paper for the simultaneous detection of two different analytes using the surface plasmon resonance (SPR) technique. The sensor employs a 50 nm-thick layer of chemically stable gold on both cleaved surfaces of the PCF to induce the SPR effect. This configuration offers superior sensitivity and rapid response, making it highly effective for sensing applications. Numerical investigations are conducted using the finite element method (FEM). After optimizing the structural parameters, the sensor exhibits a maximum wavelength sensitivity of 10000 nm/RIU and an amplitude sensitivity of -216 RIU -1 between the two channels. Additionally, each channel of the sensor exhibits its unique maximal wavelength and amplitude sensitivities for different refractive index (RI) ranges. Both channels demonstrate a maximal wavelength sensitivity of 6000 nm/RIU. In the RI range of 1.31-1.41, Channel 1 (Ch1) and Channel 2 (Ch2) achieved their maximum amplitude sensitivities of -85.39RIU -1 and -304.52 RIU -1 , respectively, with a resolution of 5×10 -5 . This sensor structure is noteworthy for its ability to measure both amplitude and wavelength sensitivity, providing enhanced performance characteristics suitable for various sensing purposes in chemical, biomedical, and industrial fields.

Design of pseudo brain nano gold layer photonic crystal fiber sensor and investigation of fabrication accuracy

In this research, a new photonic crystal fiber sensor is proposed based on human brain scan images. As the human brain analyzes information in the cerebellum to make decisions, the use of this design and placement of air holes in the shape of human brain is the main reason of more electromagnetic field limitation in the center of the fiber or pseudo-cerebellum. Finite element method based on mode solver (FEM) is used to analyze this sensor. The size of the air holes and the thickness of the plasmonic layer are proposed in this design based on the Nelder-Mead optimization algorithm. The possible errors caused by the sensor fabrication are investigated and a unique equation is presented to estimate the effect of the size of the air holes on the sensor confinement loss. Numerical inference show that this brain shape sensor has an amazing maximum amplitude sensitivity (AS) of 7208 RIU−1 and appropriate maximum wavelength sensitivity (WS) of 10000 nm/RIU. Therefore, the proposed sensor has great prospects for medical, chemical and pharmaceutical measurements and diagnostic applications because of its high sensitivity, powerful detection and easy fabrication.

Highly sensitive dual core photonic crystal fiber-based LSPR sensor with simultaneous multi-analyte detection of a wide refractive index range

This manuscript introduces an anisotropic highly sensitive dual core photonic crystal fiber sensor based on localized surface plasmon resonance, possessing the ability to detect multiple analytes simultaneously. Liquid analytes having a refractive index (RI) within the range of 1.25 to 1.5 RIU have been investigated using the proposed sensor. The numerical analysis of the sensing parameters for the proposed sensor shows a maximum wavelength sensitivity of 47,500 nm/RIU for x-polarization (Channel 1) and 18,050 nm/RIU for y-polarization (Channel 2), respectively using the wavelength interrogation technique. Maximum amplitude sensitivity of 625 RIU−1 and 437 RIU−1 is obtained for x−pol. and y−pol., respectively using the amplitude interrogation technique. Maximum sensor resolution of 2.11 × 10−6 RIU and 5.01 × 10−6 RIU is obtained for x−pol. and y−pol., respectively. The linear relationship of the resonant wavelength with the RI produces R2 = 0.9976 and R2 = 0.9979, corresponding to a degree (3) for x−pol. and y−pol., respectively. The figure of merit for x−pol. and y−pol. are 84 RIU−1 and 123 RIU−1.

A High-Sensitivity Fiber Biosensor Based on PVDF-Excited Surface Plasmon Resonance in the Terahertz Band

In this paper, a D-type photonic crystal fiber (PCF) with Zeonex material as the substrate and polyvinylidene fluoride (PVDF) material as the surface plasmon resonance (SPR) excitation layer is proposed for biosensing in the terahertz (THz) band. Analyzed with a finite element method, the proposed biosensor has shown excellent sensing properties for analyte refractive indices ranging from 1.32 to 1.45. With a maximum sensor resolution of 8.40 × 10−7 refractive index unit (RIU) and a figure of merit of 39.42 RIU−1, the maximum wavelength sensitivity and amplitude sensitivity can reach 335.00 μm/RIU and −66.01 RIU−1, respectively. A ±2% fabrication tolerance analysis is also performed on the biosensor to prove its practical feasibility. We conclude that our proposed PCF biosensor utilizing PVDF-excited SPR can provide high sensitivity, and thus a compact, label-free, and convenient solution for biomedical liquid sensing in the THz band.

Analysis of a highly temperature-sensitive gold-coated plasmonic biosensor for analyte detection

A temperature-sensitive gold coated PCF-based surface plasmon resonance (SPR) biosensor was examined for detecting analytes based on their refractive indices. The proposed sensor attained maximum amplitude sensitivities (AS) of 1432 RIU−1 and 1291 RIU−1, wavelength sensitivities (WS) of 13,500 nm/RIU and 13,000 nm/RIU in X and Y- polarized mode individually in RI spectrum of 1.34–1.4. Furthermore, the proposed sensor produced ultimate figure of merit (FOM) values of 546.93 RIU−1 and 521.4601 RIU−1 in x and y polarization modes. High birefringence of 1.5 × 10−3 was also computed for the suggested sensor. Additionally, the proposed sensor shows high temperature sensitivity of 4.5833 nm/°C with a comparable resolution of 2.18××10−2 °C and a maximum FOM value of 0.101 °C−1 in the detection range of −114 °C to 78 °C in the presence of ethanol as a sensing medium. The reported sensor therefore can be considered as a notable solution for any chemical or biological analytes detection.

Characterization of incompletely coated D-shaped PCF-SPR refractive index sensors

To reduce the complexity of the sensor structure and improve the sensitivity of refractive index (RI) measurement, a D-shaped photonic crystal fiber (PCF) surface plasmon resonance (SPR) RI sensor with incomplete coating of gold-tantalum pentoxide (Au-Ta2O5) on the surface is proposed. When the coating width is 3.1 μm, the sensor can detect RI samples ranging from 1.35 to 1.41 in the ultra-wide near-infrared (NIR) region of 1100–2100 nm wavelength. Its maximum wavelength sensitivity is 20,000 nm RIU−1, maximum amplitude sensitivity is 2817.7 RIU−1, resolution is RIU, and figure of merit (FOM) is 333.3 RIU−1. This sensor can be widely used in biological tissue detection. For this type of incomplete coated D-shaped sensor, the coating material and structural parameters not only affect the performance of the sensor, but also change the RI detection range, which has been ignored or not mentioned in previous literature on PCF-SPR sensors. Therefore, the reasons for the change of RI detection interval and negative optimization caused by structural parameters were analyzed, and two different sensors with different coating widths were finally obtained, which can achieve high sensitivity sensing in their respective detection intervals. The detailed research results expand the understanding of the SPR phenomenon in D-shaped PCF and provide theoretical guidance for adjusting and improving the detection performance of PCF-SPR sensors.

An asymmetric slotted structured twin core photonic crystal fiber based highly sensitive surface plasmon resonance refractive index biosensor

A butterfly-shaped core photonic crystal fibers with less asymmetric rectangular and circular air holes are proposed, and their properties are numerically analyzed. The sensor construction is reduced to only seven air holes and uses surface plasmons stimulated inside gold (Au) strips for simplicity in manufacture and high sensitivity. Gold is employed as an effective plasmonic metal throughout this design to create resonant effects and is located away from the proposed structure to make production easier. Maximum amplitude sensitivity for the proposed sensor is 228.89 RIU−1, maximum wavelength sensitivity is 88,000 nm/RIU, and maximum wavelength resolution is 1.14 × 10−6RIU−1 for y-polarized mode where the figure of merit is 65.78 RIU−1 with a linearity of 0.9905. The proposed sensor can detect the RI of unspecified analytes between 1.27 and 1.40, allowing for the analysis of many different types of analytes, such as viruses, cancer cells, sugars, proteins, DNA/RNA and many more.

Design and analysis of a highly sensitive SPR based PCF biosensor with double step dual peak shift sensitivity

This paper introduces a comprehensive study of a quad-cluster multi-functional Photonic Crystal Fiber (PCF) sensor where gold and Aluminum doped with zinc oxide (AZO) were used as plasmonic materials. A maximum Amplitude Sensitivity (AS) of 5336 RIU−1 and Wavelength Sensitivity (WS) of 40,500 nm/RIU in y pol was obtained incorporating Gold as plasmonic material. When AZO was included as the plasmonic material, AS of 3763 RIU−1 & WS of 9100 nm/RIU for y polarization were determined. The RI detecting range was increased from 1.32 to 1.43 to 1.19–1.42 after using AZO instead of Au that opens up a new horizon for detection. A novel detection technique, ‘Double Step Dual Peak Shift Sensitivity (DS-DPSS)’ was proposed in sensing temperature where highest sensitivity of 1.05 nm/°C having resolution of 0.095 °C for x pol. was achieved. Due to its diverse functionality, the suggested sensor represents a significant advancement in the detection of numerous analytes in biochemical applications.

Dual core photonic crystal fiber based plasmonic refractive index sensor with ultra-wide detection range.

In this study, an ultra-wide range plasmonic refractive index sensor based on dual core photonic crystal fiber is suggested and analyzed numerically. The proposed design achieves fabrication feasibility by employing external sensing mechanism in which silver is deposited onto the flat outer surface of the fiber as plasmonic material. A thin layer of titanium oxide (TiO2) is considered on top of the silver layer for preventing its oxidation problem. The sensor attains identification of a vast array of analytes consisting a wide range of refractive indices of 1.10 - 1.45. It achieves a maximum spectral sensitivity of 24300 nm/RIU along with its corresponding resolution of 4.12 × 10-6 RIU. The maximum figure of merit of the sensor is 120 RIU-1. The sensor also supports amplitude interrogation approach and exhibits a maximum amplitude sensitivity of 172 RIU-1. The impact of the design parameters such as radius of air holes, polishing distance, thickness of silver and titanium oxide layers are investigated thoroughly. An ultra-wide detection range with high sensitivity, fabrication feasibility, and easy application make the sensor a potential candidate for detection of a wide array of bio-originated materials, chemicals, and other analytes.

A comparative analysis of a D-shaped photonic crystal sensor based on graphene plasmonic

In this paper, a D-shaped photonic crystal fiber (PCF) sensor based on surface plasmon resonance has been presented. In the proposed structure, Graphene, Gold, and Silver have been used in different configurations in order to promote the sensitivity of the sensor. According to the numerical simulations performed by the finite element method (FEM) and considering the refractive index of the analyte from 1.36 to 1.40, the maximum wavelength sensitivity of 12600 nm RIU−1 has been obtained, which is related to the structure when the Gold layer sandwiched between two Graphene layers. This is while, the maximum amplitude sensitivity of the proposed sensor is 5708 (RIU−1), which is related to the configuration that Graphene has been placed under the Silver layer. On the other hand, the proposed structure is easy to use because there is no need to fill the fiber holes with the analyte and it can be easily placed on the D-shaped surface of the sensor. The proposed sensor is appropriate to sense the biological variation because of showing strong surface plasmon resonances. The effect of the fabrication tolerance on the proposed PCF is also studied. It is expected that the proposed model will be compatible with the bio-engineering approaches.

Au-strip structure dependent performance investigation of D-shaped SPR sensors for biosensing applications

Surface Plasmon Resonance (SPR)-based sensing technologies show great promise in diverse applications (e.g. biosensing) as one of the most innovative and exciting label-free sensing techniques in the last few years. In general, SPR-based sensors combine metal and dielectric interfaces, where the oscillation of metal’s free electrons occurs by the incident incoming photons. Thus, the SPR signal strength depends on the metal’s optical properties as well as the surrounding dielectric medium. This work thoroughly investigates the performance of a single mode D-shape SPR-based refractive index (RI) sensor with its gold (Au) strip topology to improve the detection sensitivity. Seven distinct Au strip designs: single-arc, inverted single-arc, multi-arc, inverted multi-arc, half-circle, coil, and sinusoidal wave are introduced to explore sensor performances, which are investigated numerically using Comsol Multiphysics. Systematic investigations are carried out for all seven proposed designs and relative comparisons are made in terms of sensitivity (wavelength and amplitude), resolution, and figure of merit (FoM). Coil and sinusoidal wave-shaped designs show excellent performance among all seven designs with a wide range of analytes’ RI (i.e. 1.31 to 1.39). The maximum wavelength and amplitude sensitivities are found to be 48000 nm/RIU and 18.55 RIU−1 respectively, with a wavelength resolution of 2.08 × 10-6 RIU and a consequent FoM of 141.18 RIU−1 for the sinusoidal wave-shaped Au-strip design. Alternatively, the coil-shaped design shows the maximum wavelength and amplitude sensitivities of 45000 nm/RIU and 32.17 RIU−1 respectively, with a wavelength resolution of 2.22 × 10-6 RIU and a FoM of 85.71 RIU−1. As a wide range of analyte’s RI can be detected by the proposed sinusoidal wave and coil Au-strip-based D-shaped sensors with improved sensitivity, these designs could be effectively used for the detection of different bio-analytes.

Au-TiO2 Coated Photonic Crystal Fiber Based SPR Refractometric Sensor for Detection of Cancerous Cells.

A surface plasmon resonance (SPR) refractometric sensor based on gold (Au) and titanium dioxide (TiO2) coated Photonic Crystal Fiber (PCF) is presented for the quick detection of various types of cancerous cells. The cancerous cells and their corresponding normal cells are both considered to be liquid cells each with their unique refractive index (RI). Normally these cells are found in liquid form in the suitable media (food) required to live the cancerous/normal cell lines. Also in our detection case, liquid samples are easy to pump into the sensing channel of the proposed PCF by employing either pressure or capillary forces.The proposed PCF sensor works on the SPR principle, with the Au coating serving as the plasmonic material. This sensor is investigated using the COMSOL Multiphysics software computational tool that is based on the full-vector finite element method (FEM). A TiO2 coating has been applied to enhance adhesion between the Au layer and the PCF surface. Above the Au coating, cancerous cells samples are filled into the PCF. When the core mode of the PCF is coupled with the surface plasmon polariton (SPP) mode under the specific resonance circumstances, SPR will occur on the interface of the gold-sample cell, and in the core mode, the loss peak is observed at the resonance wavelength. Cancerous cells samples have a distinct loss peak than normal cells samples therefore the cancerous cells can be diagnosed by measuring the shift in resonance wavelength corresponding to the loss peak of cancerous and their normal cells samples. The proposed sensor may identify various cancerous cells such as MDAMB-231, MCF-7, PC12, HeLa, and Jurkat for the diagnosis of breast cancer type-1, breast cancer type-2, adrenal glands, cervical, and blood cancer respectively. The computed wavelengths sensitivities of the proposed PCF are 9428.57nm/RIU, 10714.28nm/RIU, 7571.43nm/RIU, 5500nm/RIU, and 6000nm/RIU for the MDAMB-231, MCF-7, PC12, HeLa, and Jurkat cancerous cells, respectively. However, for various cancerous cells, the maximum amplitude sensitivity varies from -1387 RIU-1 to -1599 RIU-1. Moreover, the sensor resolution ranges between 0.93 ×10-5 RIU and 1.82 ×10-5 RIU with a 0.024 maximum detection limit. Because of its improved sensing capability, the presented SPR refractometric sensor is appropriate for the early detection of cancerous cells.

Wearable Piezoelectric Films Based on MWCNT-BaTiO3/PVDF Composites for Energy Harvesting, Sensing, and Localization

Polymer-based lead-free piezoelectric composites provide environmentally friendly and scalable space for energy conversion and structural health monitoring. In this paper, multi-walled carbon nanotubes (MWCNT)-BaTiO3/polyvinylidene fluoride (PVDF) piezoelectric composite films for energy harvesting, sensing, and localization were prepared. The highest β-phase content of 90.21% in PVDF composite nanofibers was achieved owing to the synergistic effect of MWCNT and BaTiO3 nanoparticles. The open-circuit voltage of the flexible piezoelectric nanogenerator based on interdigital electrodes reached 11.4 V at 2 Hz and a bending strain of 4 mm with an optimal power and power density of 8.67 μW and 1.16 μW/cm2, respectively, and can light up to 8 LED lights simultaneously. The output voltage did not decay during 1800 cycles, which met the power and stability requirements of a commercial capacitor. In addition, the prepared piezoelectric sensors exhibited anisotropy and high sensitivity. They had a maximum amplitude sensitivity of 93 dB, which was superior to the reported PVDF-TrFE sensors and suitable for low-frequency signal monitoring in the range of 20–40 kHz. Localization accuracy was greater than 90% in linear and planar localization tests, demonstrating the potential of preparing acoustic emission sensors. These properties facilitate the reduction of the quantity of sensors required to identify the source of damage.

Design and numerical analysis of a highly sensitive nano-layer coated photonic crystal fiber biosensor

In this paper, a highly sensitive diabetes detection sensor based on photonic crystal fiber-gold plasmonic material is designed, proposed and analyzed. In this sensor, the application of a gold thin film increases the operating wavelength range (400 nm–1200 nm). The analyte, which is the cell, is placed outside the sensor and makes it easy to fabricate. The proposed sensor detects healthy and diabetic cells based on the refractive indices. Moreover, full-transistor modeling is presented to detect the probability of diabetes. In this model, healthy persons, persons with a low risk of diabetes and persons with a high risk of diabetes are diagnosed. Numerical results show that the proposed biosensor has a maximum amplitude sensitivity of 2127.7 RIU−1, amplitude resolution of 4.69 × 10−6 RIU, maximum wavelength sensitivity of 21 000 nm RIU−1 and wavelength resolution of 4.76 × 10−7 RIU.