Faculty Publications

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Author: search.filters.author.Raghuwanshi, S.K.Subject: search.filters.subject.Scanning electron microscopy

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    High-Resolution Fiber Optic Sensor based on Coated Linearly Chirped Bragg Grating
    (Elsevier GmbH, 2020) Singh, M.; Raghuwanshi, S.K.; Prakash, O.; Kumar, P.K.
    a fiber optic strain sensor is proposed and experimentally demonstrated using fiber Bragg grating (FBG) based interrogation scheme. Due to fast response time and better sensitivity of graphene oxide (GO) material, coated linearly chirped fiber Bragg grating (LCFBG) is used in this work. Interrogation scheme is used for the efficient strain sensing by placing LCFBG within the Sagnac loop (wavelength dependent receiver). The GO deposition is confirmed by ultraviolet–visible spectroscopy, atomic force microscopy (AFM), and field emission scanning electron micrograph (FESEM). Our proposed fiber optic strain sensor possesses better resolution, stable operation in the infra-red region. In addition, sensor demonstrates 5.25 ?? static strain and 0.645 ??/?Hz dynamic strain resolutions, respectively. © 2020 Elsevier GmbH
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    Real-time interrogation of fiber optic biosensor using TiO2coated etched long-period grating
    (American Institute of Physics Inc., 2020) Singh, M.; Raghuwanshi, S.K.
    In this work, a TiO2 coated etched long-period grating (e-LPG) fiber optic biosensor is developed for the detection of Escherichia coli (E. coli) bacteria in food items. Label-free Escherichia coli bacteria monitoring is done over the detection range of 0 cfu/ml-50 cfu/ml using an advanced spectral interrogation mechanism. The thin film deposition of 40 nm TiO2 over the e-LPG is confirmed by the microscopy method, such as scanning electron microscopy. In our proposed biosensor design, T4-bacteriophage is covalently immobilized over the TiO2 coated fiber surface. This biosensor system has reached sensitivity at 2.55 nm/RIU. Our experiments confirm the resolution and the limit of detection (3?/S) of 0.0039 RIU and 10.05 ppm, respectively. The proposed biosensor with enhanced sensitivity is suitable for monitoring harmful pathogens/infectious agents in various food products. © 2020 Author(s).