S. Nivedha

Bio: S. Nivedha is an academic researcher from VIT University. The author has contributed to research in topics: Photonic-crystal fiber & Surface plasmon resonance. The author has an hindex of 3, co-authored 4 publications receiving 19 citations.

Surface Plasmon Resonance:Physics and Technology

Abstract: Over the last few decades, surface plasmon resonance (SPR) technique has been very promising for sensing applications. It involves light-matter interaction at the interface of the metal and dielectric. This technology is employed in physical, chemical and biological sensing applications. In this review, we present the principle of SPR, different configurations used for excitation of SPR, performance characteristics of a sensor and commercialization of the biosensors technology. A few applications of SPR as biosensors have also been reviewed in this article.

Designing a refractive index based biosensor using a photonic quasi-crystal fiber

Abstract: We design a ten-fold photonic quasi-crystal fiber using finite element method. Further, we explore various optical characteristics and exploit them for realizing a biosensor. We achieve a maximum refractive index sensitivity of 29000 nm/RIU and a resolution of 3.4 × 10−6 RIU a sensing range of 1.47–1.48.

Design of a Terahertz Alcohol Sensor Using a Steering-Wheel Microstructured Photonic Crystal Fiber

Abstract: In this paper, we design a novel photonic crystal fiber (PCF) chemical sensor wherein the cladding structure is made of a steering-wheel (SW)-shaped large non-circular air-hole. In this PCF, we int...

Principles Of Optics Electromagnetic Theory Of Propagation Interference And Diffraction Of Light

Abstract: Thank you for reading principles of optics electromagnetic theory of propagation interference and diffraction of light. As you may know, people have search hundreds times for their favorite novels like this principles of optics electromagnetic theory of propagation interference and diffraction of light, but end up in harmful downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they are facing with some infectious bugs inside their computer.

High performance dual core D-shape PCF-SPR sensor modeling employing gold coat

Abstract: In this paper, an enhanced performance of dual core D-shape photonic crystal fiber utilizing surface plasmon resonance (DD-PCF-SPR) based sensor is numerically proposed and analyzed. The thickness of gold and pitch parameter are optimized to 30 nm and 1.9 um, respectively, which ensures superior sensor performance. It is revealed; at optimized geometrical parameter, the offered sensor displays a supreme wavelength sensitivity of 8000 nm/RIU, wavelength resolution of 1.25 × 10−5 RIU, a supreme amplitude sensitivity of 700 RIU−1, amplitude resolution 1.7857 × 10−5 RIU and a figure of merit (FoM) of 138 RIU−1 due to the analyte refractive index changing from 1.47 RIU to 1.48 RIU. The identifying features are investigated using modal analysis based finite element method (FEM) incorporating COMSOL commercial software. Finally, a relative review is executed comparing amplitude sensitivity, resolution and wavelength sensitivity of the offered sensor with previously reported sensors. As high sensitivity, simple structure, and tremendous linear polynomial characteristics, the offered sensor will be a talented candidate for the detection of various biochemical and biological samples (DNA, mRNA, proteins, sugar).

A Theoretical Proposal for a Refractive Index and Angle Sensor Based on One-Dimensional Photonic Crystals

Abstract: In this article, a structure based on one-dimensional photonic crystals that can be used for both angle sensing and refractive index sensing is proposed, which is achieved by optical Tamm state. Under Bragg scattering, its features are investigated by the transfer matrix method. This sensing structure is based on a multi-frequency absorption structure, which can achieve an absorption rate higher than 0.9 for three to four frequency points at the same time. The studied results demonstrate that the absorption peaks of such an absorption structure can be changed from three to four by adjusting the number of periods and silver layer thickness. Absorption peaks can occur red and blue shifts employing tailoring the thickness of defect and the angle of the incident light. By altering the thickness of the defect and the number of periods, the interval between the absorption peaks can be dominated. They are all with high-quality factors and can be used to bring about a high absorption sensor for the refractive index or angle. When it acts as a refractive index sensor, the operating range can cover from 2 to 2.7, whose sensitivity and average figure of merit are 32.3 THz/RIU and 100. If the presented device is used as an angle sensor, those values will become 0.5 THz/degree and 1.2, and its measuring range is from 25° to 70°. It can be said that the emergence of this special sensing structure will be possible to have a broad application prospect in the field of measurement.

Critical assessment of relevant methods in the field of biosensors with direct optical detection based on fibers and waveguides using plasmonic, resonance, and interference effects.

Abstract: Direct optical detection has proven to be a highly interesting tool in biomolecular interaction analysis to be used in drug discovery, ligand/receptor interactions, environmental analysis, clinical diagnostics, screening of large data volumes in immunology, cancer therapy, or personalized medicine. In this review, the fundamental optical principles and applications are reviewed. Devices are based on concepts such as refractometry, evanescent field, waveguides modes, reflectometry, resonance and/or interference. They are realized in ring resonators; prism couplers; surface plasmon resonance; resonant mirror; Bragg grating; grating couplers; photonic crystals, Mach-Zehnder, Young, Hartman interferometers; backscattering; ellipsometry; or reflectance interferometry. The physical theories of various optical principles have already been reviewed in detail elsewhere and are therefore only cited. This review provides an overall survey on the application of these methods in direct optical biosensing. The "historical" development of the main principles is given to understand the various, and sometimes only slightly modified variations published as "new" methods or the use of a new acronym and commercialization by different companies. Improvement of optics is only one way to increase the quality of biosensors. Additional essential aspects are the surface modification of transducers, immobilization strategies, selection of recognition elements, the influence of non-specific interaction, selectivity, and sensitivity. Furthermore, papers use for reporting minimal amounts of detectable analyte terms such as value of mass, moles, grams, or mol/L which are difficult to compare. Both these essential aspects (i.e., biochemistry and the presentation of LOD values) can be discussed only in brief (but references are provided) in order to prevent the paper from becoming too long. The review will concentrate on a comparison of the optical methods, their application, and the resulting bioanalytical quality.