Refractive Index Of Prism Research Articles

Lossy Mode Resonance Sensors Based on Anisotropic Few-Layer Black Phosphorus.

Lossy mode resonance (LMR) sensors offer a promising avenue to surpass the constraints of conventional surface plasmon resonance (SPR) sensors by delivering enhanced label-free detection capabilities. A notable edge of LMR over SPR is its excitation potential by both transverse electric (TE) and transverse magnetic (TM) polarized light. Yet this merit remains underexplored due to challenges to achieving high sensing performance under both TM and TE polarization within a singular LMR model. This study introduces a theoretical model for an LMR prism refractive index sensor based on a MgF2-few layer black phosphorus-MgF2 configuration, which can achieve angular sensitivity nearing 90° refractive index unit-1 (RIU-1) for both polarizations. Leveraging the distinct anisotropic nature of black phosphorus, the figure of merit (FOM) values along its two principal crystal axes (zigzag and armchair) show great difference, achieving an impressive FOM of 1.178 × 106 RIU-1 along the zigzag direction under TE polarized light and 1.231 × 104 RIU-1 along the armchair direction under TM polarized light. We also provide an analysis of the electric field distribution for each configuration at its respective resonant conditions. The proposed structure paves the way for innovative applications of anisotropic-material-based LMR sensors in various applications.

Modeling and analysis of discrete particle detection in wide-field surface plasmon resonance microscopy

Wide-field surface plasmon resonance microscopy (WF-SPRM), based on Kretschmann’s configuration, is a powerful technique for detecting nano-objects in solution. In this study, key parameters for building a highly sensitive WF-SPRM are optimized, including laser wavelength, prism refractive index, numerical aperture of the objective, and gold layer thickness. A medium model describes the surface plasmon resonance (SPR) sensor principle, treating molecules bound on the sensor surface as an effective medium with an effective refractive index and thickness. On the other hand, the SPR discrete particle model is introduced to describe the detection principle for discrete particles. Theoretical, numerical, and experimental analyses are conducted, and the calculated intensity profiles of single and double nanoparticles from the discrete particle model describe the experimental profiles well. Furthermore, the influence of coating the gold layer with a dielectric layer on the SPR sensitivity is investigated for varying refractive indices.

Enhanced refractive index sensing using a surface plasmon resonance sensor with heterostructure

This article aims to enhance the sensitivity of a surface plasmon resonance sensor for refractive index sensing in the visible region using a low refractive index prism. The proposed sensing system is ultrasensitive and employs an angular interrogation method for measuring reflected intensity. The bimetallic layers and two-dimensional heterostructure are utilized to increase sensitivity. Black phosphorus is utilized as an analyte-interacting layer due to its sp3 hybridized puckered structure, high charge carrier density, indirect bandgap and larger surface area for attachment of analyte. To optimize the sensor structure and architecture based on its sensitivity and figure of merit, a comprehensive analysis is performed. The proposed sensor achieves the best possible sensitivity of 345.83°/RIU, detection accuracy of 0.132 Deg−1 and figure of merit of 45.74/RIU. This work enables to design a highly sensitive refractive index sensor useful to sense small sized analyte. The proposed research work provides new dimension to develop highly sensitive refractive index sensor for biomolecule or biochemical sensing.

Multi-Parameter Model-Based Polarimetric Calibration for Dual-Coded Spectral Polarization Imaging System

A polarization analysis method based on a multi-parameter model is proposed to address the polarization effect analysis and calibration requirements of a dual-coded snapshot spectral polarization imaging system. A full-link polarization effect model for a spectral polarization imaging system is established that includes a digital micromirror array (DMD), prism grating prism (PGP), micro-polarizer array detector (MPA), and multi-film. The influence of parameters such as the refractive index, incident angle, grating refractive index, constant, prism refractive index, vertex angle, multi-layer film complex refractive index, and film thickness on the optical transmittance of the system are analyzed. Using a dynamic data exchange mechanism to perform full-link, full-FOV, and full-pupil ray tracing on the optical system, the polarization effect distribution of the system under different degrees of polarization (DOP) and wavelengths is obtained. A calibration experiment for the controllable incident wavelength and DOP using narrowband filters and glass stacks is established. The experimental results show that in the 420 nm, 532 nm, and 635 nm wavelength bands, the MSEs of the calibrated values are 1.3924 × 10−4, 1.6852 × 10−4, and 1.6735 × 10−4, respectively. It is proven that the calibration method based on a multi-parameter model is feasible. Finally, the spectral polarization image at 532 nm is calibrated. The contrast ratio of metallic aluminum is calibrated from 7.13 to 15.33. This study provides a theoretical basis for the analysis and calibration of polarization effects in a dual-coded snapshot spectral polarization imaging system.

Detection of blood cancer using highly sensitive surface plasmon resonance sensor based on MXene 2D nanomaterial

The most common disease on the earth, cancer, has raised concerns about the health of humans. Early discovery is a crucial argument to increase treatment success. A surface plasmon resonance (SPR) biosensor having prism, silver, MXene and analyte is theoretically proposed and numerically simulated in this work for rapid and accurate detection of blood cancer cells. Many different prisms are examined. The structure with the lowest refractive index prism has shown the highest sensitivity, hence it is taken into consideration for additional studies. Since an MXene layer has a larger surface area, it enhances surface-biomolecule adsorption. The number of MXene sheets and silver layer thickness are optimized to improve the sensor sensitivity. The SPR sensor can attain a sensitivity of 232.25 deg/RIU for 50 nm silver with a bi-layer of MXene. We believe that the proposed sensor has a very simple structure to facilitate the fabrication and it will be encouraging to be used in biosensing.

A Highly Sensitive Sensing Technique via Surface Plasmons With Tunable Prism Refractive Index

A new perspective using Kretschmann configuration is presented to excite surface plasmon polaritons (SPP) at liquid crystal (LC)/metal interface. The excitation of SPP takes place through the electrical tuning of the prism refractive index instead of the commonly used angular interrogation. The results show that the proposed methodology is 30% superior to the traditional angular interrogation. The 5CB (4-pentyl-4’-cyanobiphenyl) is one of the best suited nematic LC material for the proposed detection framework. Its refractive index is linearly tunable in the range 1.55 ~ 1.78 (at wavelength 1.55 μm) via an external applied electric field. In that range of refractive index variation, the SPP modes are efficiently excited; and hence any minute variation in the analyte refractive index can be detected reliably and accurately through a simple tuning of the refractive index of the prism LC material. The fundamental characteristics of the sensor are assessed through the evaluation of the linearity, sensitivity (S), the full width at half maximum (FWHM) of the reflectivity curve and the figure of merit (FOM). The variation of these characteristics over a whole range of analyte refractive index (1.3–1.4) are presented as well. The electrical tuning provides a well-matched design with micro-scale devices.

A Theoretical analysis of Milk adulteration/contamination detection in camel, buffalo and cow milk using SPR Technique

In this paper author have targeted to detect various kinds of adulteration/contamination in camel, cow and buffalo milk using surface plasmon resonance (SPR) technique. SPR technique have numerous features like its label free technique, provide real time analysis and able to detect very minute change in sample’s physical condition from its ideal condition. The change in sample physical condition change can estimate using change in refractive index. The adulteration in milk does for financial benefits but they are highly dangerous for health especially for children and pregnant women. Some more contamination added knowingly as a preservative but they affect the purity of milk so that their detection is essential. In this paper author have targeted to detect mainly urea, melamine, Salmonella and coconut oil in milk by using a Kretschmann configuration based SPR sensor. The sensor consists of high refractive index prism (ZnSe) as a dielectric substrate, gold (Au) nanolayer, Graphene monolayer and heterostructure of BlueP/MoS2. Major performance parameters like sensitivity, Figure of Merit (FoM), Detection accuracy and limit of detection also calculated for each case to validate the result of proposed sensor. The performance of sensor is done in visible region in theoretical way using analytical software MATLAB.

Effect of 2-D nanomaterials on sensitivity of plasmonic biosensor for efficient urine glucose detection

This paper presents a multi-layered Kretschmann configuration-based Surface Plasmon Resonance (SPR) biosensor for the detection of urine glucose. The modelling, simulation, and analysis have been done by using Silver (Ag) and Gold (Au) layer on the low refractive index prism BK-7 separately, which created two structures: structure-I (BK7/Ag/Bio-sample) and structure-II (BK7/Au/Bio-sample). Urine samples from a non-diabetic person (0–15 mg/dL) and a diabetic person (.625 gm/dL, 1.25 gm/dL, 2.5 gm/dL, 5 gm/dL, and 10 gm/dL) with the corresponding refractive indices of 1.335, 1.336, 1.337, 1.338, 1.341, and 1.347, respectively, have been used as a bio-sample that has been put on the top layer of the sensor. An investigation was conducted to improve the performance parameters of the proposed plasmonic biosensor by layering different 2-D nanomaterials (graphene, BP) and TMDC materials (MoS2, MoSe2, WS2, and WSe2) over the silicon (Si) layer in both structures at a visible wavelength of 633 nm, using Transfer Matrix Method (TMM). With layer thickness optimization, Structure-I (BK7/Ag (56 nm/Si (3 nm)/WS2 (.8 nm)/Bio-sample) shows a sensitivity of 200 °/RIU which is enhanced up to 1.7 times that of the conventional biosensor (BK7/Ag/Bio-sample) and 1.3 times that of the BK7/Ag (56 nm)/Si (3 nm)/Bio-sample based biosensor. Whereas in Structure-II (BK7/Au (50 nm)/Si (3 nm)/BP (.53 nm)/Bio-sample) with optimised layer thickness, we obtained a sensitivity of 273.4°/RIU, which is enhanced up to 2.2 times that of the conventional biosensor (BK7/Au/Bio-sample) and 1.3 times that of the BK7/Au (50 nm)/Si (3 nm)/Bio-sample. Other performance parameters such as detection accuracy for Structure-I and Structure-II are .5617 degree−1 and .134 degree−1 respectively. The Figure of merit for Structure-I and Structure-II are 112.35/RIU and 36.89/RIU respectively. Therefore, we expect Structure-I (BK7/Ag (56 nm/Si (3 nm)/WS2 (.8 nm)/Bio-sample) and Structure-II (BK7/Au (50 nm)/Si (3 nm)/BP (.53 nm)/Bio-sample) have the potential to detect the glucose concentration with quick response and high sensitivity in terms of the resonance angle shift in SPR curves.

Simplified and Improved Measurement of Prism Apex Angle and Refractive Index Using a Spectrometer

Simplified and Improved Measurement of Prism Apex Angle and Refractive Index Using a Spectrometer

Solar Angle Model for Daylight Redirection in Prismatic Panel

An advanced complex fenestration system can utilize uniform daylight. Nonetheless, an inefficient design would increase solar heat gain and indoor temperatures, besides uneven light distribution that would cause the "cave effect." Prismatic panels are widely used as complex fenestration systems, providing uniform daylight. This paper proposes a computational model that integrates optical principles like Snell's law with environmental variables and visualizes the performance of prismatic panels in terms of redirection angle while encountering the prism refractive index and geometry at the specified geographic location. The proposed model entails a prismatic panel as a daylight system for redirecting daylight. In contrast to detailed modeling needed for simulation in software programs like Radiance, this computational tool provides a more straightforward and efficient solution for the initial design of light redirection panels that rely on the principle of refraction and evaluate their annual performance based on the angle of deviation. The model's applicability has been demonstrated by utilizing various triangular prism design examples with diverse materials in Frankfurt and Helsinki.

Autofluorescence Imaging of Living Yeast Cells with Deep-Ultraviolet Surface Plasmon Resonance

Autofluorescence in living cells on aluminum thin film was excited with deep-ultraviolet surface plasmon resonance (deep-UV SPR). Deep-UV SPR under aqueous medium was excited with Kretschmann configuration by using a sapphire prism. Deep-UV SPR is one of the promising techniques for high-sensitive autofluorescence imaging of living cells without staining. Label-free observation is significant for the structural analysis of living cells. We demonstrated the high-sensitive autofluorescence imaging of living yeast cells with deep-UV SPR. We applied a high refractive index prism, such as sapphire, which is suitable for the observation of specimens in aqueous medium, to excite deep-UV SPR. Although typical autofluorescence from living cells is buried in background noise, deep-UV SPR enhances the autofluorescence signal. The deep-UV SPR excitation of an aluminum thin film through a sapphire prism was investigated theoretically and experimentally. It showed that the fluorescence intensities are increased 2.8-fold. Deep-UV SPR enhanced the autofluorescence of cell structures, and yeast cells were found to be very sensitive. As a result, for water-immersed specimens, the sapphire-prism-based Kretschmann configuration excited SPR in deep-UV. Findings from this study suggest that deep-UV SPR can be considered an effective technique for attaining high-sensitivity observation of biological samples.

Interaction of plasmon-exciton in a columnar dielectric thin film with a structural defect excitonic thin film

In this research, the coupling of surface plasmon-polariton and surface exciton-polariton in a multilayer structure of metallic medium and columnar dielectric thin film with excitonic spacer in Kretschmann configuration theoretically is investigated; using transfer matrix method. The effect of structural parameters such as the length of columns of columnar thin film and the rise angle of them, the refractive index of prism, the void fractions of columnar thin film and the thickness of excitonic medium on coupling are studied. The results showed that the coupling becomes strength by decreasing the length of columns of dialectic medium and refractive index of prism. Also, by reducing the volume fraction of air in columnar thin film, the coupling becomes stronger as the thickness of the excitonic medium increases and the ultra- strong coupling was obtained at fv=0.2. The energy spectrum of plexciton branches in terms of detuning frequency indicates the anti-crossover behavior of plexciton modes, which includes the coupling strength of the modes from the medium to ultra-strong region.

A high sensitivity lossy mode resonance refractive index sensor based on SBS structure

This paper presents a theoretical model of lossy mode resonance (LMR) prism refractive index sensor based on the SBS (sensing medium/black phosphorus/sensing medium) structure. By using the sensing medium as the matching layer and the black phosphorus (BP) as the lossy layer, the sensor’s performance under angular interrogation is effectively improved. In addition, the implications on the reflectance of changes in the sensor structure are investigated in detail and the principles for the design of the device are summarized in this paper. Results show that the device has a refractive index detection range of 1.33–1.49, with different sensing properties under TE and TM polarized light. This LMR sensor has a high sensitivity under TE polarized light with a sensitivity range of 83–420 °/RIU and a maximum quality factor of 9.9×105 RIU−1 under TM polarized light. We believe that the proposed structure can be broadly applied to chemical biomolecular detection, environmental monitoring, medical diagnosis, and other fields.

Pengembangan Modul Praktikum Deviasi Dan Indeks Bias Prisma Berbasis Laboratorium Virtual

Research is motivated by the lack of a virtual lab-based deviation and refractive index practicum module, so students are less experienced in using these tools while experimenting. This purpose of this research is to create a virtual lab-based module for prismatic deviation and refractive index. This research is developmental (Research and Development) using a 4D research model adopted from Thiagarajan model i.e. define, design, develop, and disseminate. The result of the group research receive an average value of 83.19%, so that the module is classified in the feasible/valid category. And in the student responses 58.35% said it was very useful (SB), 39.6% said it was useful(B), and 2.05% said it was less useful(KB), no one chose not useful(TB). Based on the result of the research, it can be concluded that a product in the form of a basic physics practicum module for the virtual laboratory-based prism deviation and refractive index tool was manufactured with good and appropriate qualifications.

CH3NH3PbBr3 Thin Film Served as Guided-Wave Layer for Enhancing the Angular Sensitivity of Plasmon Biosensor.

CH3NH3PbBr3 perovskite thin film is used as a guided-wave layer and coated on the surface of an Au film to form the Au-perovskite hybrid structure. Using the hybrid structure, a perovskite-based guided-wave surface plasmon resonance (GWSPR) biosensor is proposed with high angular sensitivity. First, it is found that the electric field at the sensing interface is improved by the CH3NH3PbBr3 perovskite thin film, thereby enhancing the sensitivity. The result demonstrates that the angular sensitivity of the Au-perovskite-based GWSPR biosensor is as high as 278.5°/RIU, which is 110.2% higher than that of a conventional Au-based surface plasmon resonance (SPR) biosensor. Second, the selection of the coupling prism in the configuration of the GWSPR biosensor is also analyzed, and it indicates that a low refractive index (RI) prism can generate greater sensitivity. Therefore, the low-RI BK7 prism is served as the coupling prism for the proposed GWSPR biosensor. Finally, the proposed GWSPR sensing structure can not only be used for liquid sensing, but also for gas sensing, and it has also been demonstrated that the GWSPR gas sensor is 2.8 times more sensitive than the Au-based SPR gas sensor.

Plasmonic Sensor Based on Molybdenum Trioxide-MXene Heterojunction for Refractive Index Sensing

The advent of MXene and its composites has witnessed remarkable applications in vibrant scientific researches. In view of this rapid development, the present work reports on the application of molybdenum trioxide (MoO3) and Ti3C2Tx MXene heterojunction in surface plasmon resonance-based sensor for sensitivity enhancement. The biocompatible Ti3C2Tx MXene layer is made in contact with the analyte. Simulated analysis of work is based on transfer matrix method utilising angular interrogation method. The sensitivity enhancement is explained on the physical phenomena of effective optical constant of multilayered structure. Moreover, the effects of prism refractive index on sensor’s performance are also studied. The highest sensitivity (268.14°/RIU) and figure of merit (44.37/RIU) values are obtained in case of SiO2 prism-based sensor configuration. This work will open new avenues for MoO3-Ti3C2Tx MXene (also other MXene families) heterojunction/heterostructure in various sensing applications.

Multi-diffractive grating for surface plasmon biosensors with direct back-side excitation.

A multi-diffractive nanostructure is reported for the resonant excitation of surface plasmons that are cross-coupled through a thin metallic film. It consists of two superimposed periodic corrugations that allow diffraction excitation of surface plasmons on the inner side of a thin metal film and their subsequent phase matching with counterpropagating surface plasmons travelling to the opposite direction on its other side. This interaction leads to establishing of a set of cross-coupled Bragg-scattered surface plasmon modes that exhibit an electromagnetic field localized on both metal film interfaces. The reported structure is attractive for surface plasmon resonance biosensor applications, where direct optical probing can be done through the substrate without the need of optical matching to a high refractive index prism. In addition, it can be prepared by mass production - compatible means with UV-nanoimprint lithography and its biosensing performance characteristics are demonstrated by refractometric and biomolecular affinity binding studies.

Designer Bloch plasmon polariton dispersion in grating-coupled hyperbolic metamaterials

Hyperbolic metamaterials (HMMs) represent a novel class of fascinating anisotropic plasmonic materials, supporting highly confined propagating plasmon polaritons in addition to surface plasmon polaritons. However, it is very challenging to tailor and excite these modes at optical frequencies by prism coupling because of the intrinsic difficulties in engineering non-traditional optical properties with artificial nanostructures and the unavailability of high refractive index prisms for matching the momentum between the incident light and the guided modes. Here, we report the mechanism of excitation of high-k Bloch-like Plasmon Polariton (BPPs) modes with ultrasmall modal volume using a meta-grating, which is a combined structure of a metallic diffraction grating and a type II HMM. We show how a 1D plasmonic grating without any mode in the infrared spectral range, if coupled to a HMM supporting high-k modes, can efficiently enable the excitation of these modes via coupling to far-field radiation. Our theoretical predictions are confirmed by reflection measurements as a function of angle of incidence and excitation wavelength. We introduce design principles to achieve a full control of high-k modes in meta-gratings, thus enabling a better understanding of light-matter interaction in this type of hybrid meta-structures. The proposed spectral response engineering is expected to find potential applications in bio-chemical sensors, integrated optics and optical sub-wavelength imaging.

HR-Si prism coupled tightly confined spoof surface plasmon polaritons mode for terahertz sensing.

We report a high-resistivity silicon (HR-Si) prism coupled terahertz (THz) spoof surface plasmon polaritons (SSPPs) on flat subwavelength metasurface. Using a high refractive index prism as an external coupler, a more tightly confined SSPPs mode can be excited in a smaller resonant cavity, leading to strong light-matter interaction. Besides, theoretical analysis and experimental results have both indicated that the SSPPs resonance response to the filling patterns of analyte in the resonant cavity are quite different. In particular, we have found that the interaction between analyte and SSPPs wave can be maximized when the analyte filled with the whole resonant cavity and a higher sensitivity for THz sensing can be obtained. A high sensitivity varied from 0.31 THz/RIU to 0.85 THz/RIU is predicted. Furthermore, these SSPPs modes exhibit high Q-factor, and characteristic spectra of water caused by surface plasmon resonance (SPR) are observed, which is significant in promoting the THz-SPR sensing of polar liquids or aqueous analytes with THz metasurfaces.

Electro optic modulation of Imbert-Fedorov effect and refractive index detection in magnetized terahertz graphene waveguide

Abstract Imbert-Fedorov (IF) effect means a transverse shift of circularly polarized light perpendicular to the incident plane when refracted from an interface. The physical mechanism of this phenomenon is the coupling between spin angular momentum and orbit angular momentum based on the angular momentum conservation law. We study electro optic (EO) modulation and refractive index detection of graphene waveguide based on IF effect. As the applied voltage affects the permittivity of graphene, EO modulated IF effect can be observed. We mainly focus on the EO modulation of IF effect in the graphene waveguide and give the physical explanations for this phenomenon. Due to the dependence of IF effect on the prism refractive index, we explore the possible application of the graphene waveguide in refractive index detection in which a maximum sensitivity of 1.4 × 104 μm/RIU can be obtained. Meanwhile the detectable refractive index range and its sensitivity can also be controlled by the applied voltage. The EO modulation of IF effect provides us a new physical mechanism to realize EO modulators and refractive index sensors.