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Subject: search.filters.subject.Surface plasmon resonance

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    Ultrasensitive surface plasmon resonance-based biosensor for efficient detection of SARS-CoV-2 Virus in the near-infrared region
    (2024) Grover, Nitika; Arora, Pankaj
    This work offers an ultra-sensitive multilayered surface plasmon resonance (SPR)-based biosensor that uses angular interrogation in the near-infrared (NIR) region to detect the novel coronavirus (SARS-CoV-2). The multi-layered biosensor consists of the bimetallic layer (Aluminum (Al) & Gold(Au)), a dielectric layer (MgF2), and an optimized number of 2D nanomaterial (MoS2) layers. The proposed SPR sensor is engineered using the transfer matrix and finite element methods to achieve high sensitivity, the figure of merit (FOM), and detection accuracy. The selection of plasmonic metal and optimization for the different layers have been proved crucial to improving the performance parameter of the proposed sensor. The biosensor configuration (Glass prism/Al/Au/MgF2/MoS2/sensing sample) is observed to exhibit the highest sensitivity of 372°/RIU, FOM of 1690 RIU-1, and detection accuracy of 4.54 degree-1 using the strong binding efficiency of the MoS2 layer and the high dielectric constant of the MgF2 layer. According to the investigation's findings, the proposed SPR-based biosensor exhibits excellent performance in the NIR region, demonstrating accurate real-time detection capabilities that will facilitate its use in field or clinical point-of-care testing applications.
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    TiO2-FG-based plasmonic sensor with enhanced figure of merit for sensing applications: A numerical approach
    (Elsevier, 2025-09) Grover, Nitika; Arora, Pankaj
    A refractive index-based surface plasmon resonance sensor using a multilayer heterostructure in the Kretschmann configuration is proposed for the near-infrared region. In the proposed configuration, aluminum is used as a plasmonic metal, titanium dioxide is used as a dielectric layer, and a fluorinated graphene (FG) layer is used as a 2D nanomaterial to enhance the performance parameters. A thorough comparative study is conducted between popularly used titanium compounds: Titanium dioxide (TiO2) and Titanium disilicide (TiSi2). For the proposed SPR sensor, each layer is engineered and optimized on the grounds of linewidth, detection accuracy (DA), and Figure of Merit (FOM), which are the critical performance parameters. To this end, the geometrical parameters are calculated using the transfer matrix method and analyzed meticulously to find the optimum trade-off points. The proposed sensor is numerically tested efficiently to sense different concentrations of hemoglobin in human blood. For the angle interrogation technique at the wavelength of 1550 nm, the sensor provides an enhanced FOM of 462.8 RIU−1 and a DA of 4 degrees−1. Thus, the proposed design opens a broader window for bio-sensing applications because of the advantages TiO2 and FG layers offer in enhancing the sensing parameters.
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    Measurement of optical anisotropy in ultrathin films using surface plasmon resonance
    (Elsevier, 2016-01) Manjuladevi, V.; Gupta, Raj Kumar
    The optical phenomenon, surface plasmon resonance (SPR) is employed for the measurement of optical anisotropy in the ultrathin films fabricated through Langmuir–Blodgett (LB) and self-assembled monolayer (SAM) techniques onto 50 nm gold film supported on BK7 glass substrates. The resonance angle (RA) is measured using a home built setup in Kretschmann configuration. The LB films and SAM can provide a single layer of highly ordered and organized molecules on the two dimensional surface. If the film forming molecules are anisotropic, their organization in the LB films and SAM can yield an anisotropic film due to tilt of the molecules with respect to the surface normal. The SPR spectra are recorded for the two orthogonal directions of the film with respect to the plane of incidence. The spectra are simulated by modeling the Fresnel's reflection from 4-layers viz., prism, gold, ultrathin films and air; and the real and imaginary parts of refractive index are estimated. Our study shows the metallic and dielectric nature of the LB films of bundles of single walled carbon nanotubes (SWCNTs) when the long axis of SWCNTs are aligned parallel and perpendicular to plane of incidence, respectively. The optical anisotropy was estimated from the change in real part of refractive index (Δnr) of the ultrathin films measured in the orthogonal directions. In addition, we have also studied such optical anisotropy in the LB film of cadmium-stearate and self-assembled monolayer of octadecanethiol.
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    Surface plasmon resonance sensor based on a new opto-mechanical scanning mechanism
    (Elsevier, 2016-05) Gupta, Raj Kumar; Manjuladevi, V.
    Surface plasmon resonance (SPR) is employed as one of the key phenomena in biological, chemical and gas sensors. In this paper, we report development of a Kretschmann configuration based SPR sensing instrument by adopting a unique opto-mechanical scanning mechanism. The new scanning mechanism ensures portable, very low-cost and sensitive SPR sensor. In contrary to the traditional scanning mechanism, we utilized a rotating mirror for changing angle of incidence, and a quadrant photodiode (QPD) for recording reflected intensity. In order to achieve constant spot measurement on the sensing area (gold surface) for a fixed referencing, the prism-sensor assembly is translated vertically in a highly controlled manner governed by a feedback mechanism. In the feedback mechanism, the deflection of reflected beam is quantified by the QPD, and the prism-sensor assembly is translated vertically so as to regain the original set point. The SPR spectra of different materials deposited onto the gold surface using different techniques were collected and studied. Using the developed SPR instrument with pure gold sensing surface, the lowest detectable concentration of the sucrose in aqueous medium was found to be 100 femto-molar. The sensitivity of the instrument was estimated using the different concentration of aqueous solutions of sucrose with known refractive indices, and it was found to be around 52.6°/RIU. These studies indicate a high resolution and good sensitivity of the instrument.
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    Design and comparative analysis of aluminum-MoS2 based plasmonic devices with enhanced sensitivity and Figure of Merit for biosensing applications in the near-infrared region
    (Elsevier, 2021-02) Arora, Pankaj
    Aluminum (Al)-Molybdenum Disulfide (MoS2) based plasmonic structures act as excellent biosensors when exploited in the near-infrared region. While Al is economical as well as compatible with the optoelectronic devices, MoS2 is an emerging 2D nanomaterial with the promise of initiating better plasmonic activity. Based on Kretschmann's arrangement, we have explored angular interrogation over four different combinations of heterostructures with Al as the plasmonic metal layer, at a wavelength of 1550 nm. After studying the effect of Al thickness on the conventional configuration, the intermediate layers between the metal layer and the analyte were optimized. Inclusion of graphene along with MoS2 results in better interaction with the sensing medium. The effect of including silicon is also studied for sensitivity enhancement. In addition, a comparative analysis of sensor performances of the proposed devices is presented taking into account the two important parameters i.e. sensitivity as well as the Figure of Merit (FOM). Among the optimized multi-layered MoS2 based configurations, a maximum sensitivity of about 141°/RIU is obtained along with FOM of about 335.13 RIU−1. Finally, the single-stranded DNA sensing on the proposed devices shows that the structures can be used as a highly sensitive refractive index biosensor for bio-medical applications.
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    Graphene decorated aluminum-nanostructure based plasmonic device with enhanced sensitivity and figure of merit using both wavelength and angle interrogation
    (Elsevier, 2022-07) Arora, Pankaj
    In this work, we have proposed graphene decorated Aluminum (Al) nanostructure-based plasmonic device for sensing in the near-infrared region where the same engineered plasmonic device can be used under both angle as well as wavelength interrogation with high sensitivity and Figure of Merit (FOM) simultaneously. A detailed analysis using rigorous coupled-wave analysis is carried out to prove the feasibility of the proposed plasmonic device with the same designed parameters to operate in two interrogation modes, which is impossible in conventional prism configuration. The performance parameters, sensitivity, and FOM are found to be 1000 nm/RIU and 333.33RIU−1 during wavelength interrogation and 119º/RIU and 318.91RIU−1 for the angle interrogation respectively. Finally, the biosensing application is carried out by demonstrating the glucose concentration detection in the urine samples. The proposed Al-based plasmonic device decorated with graphene layer has the advantages of being cost-effective and possessing real-time sensing capability, paving the way for biomedical applications in the near-infrared region.