Browsing by Author "Rajesh K B"

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AN ANALYSIS ON THE PERFORMANCE OF THE PRISM BASED SPR SENSOR WITH COMPOSITE OF INDIUM TIN OXIDE AND GOLD
(Journal of Environmental NanoTechnology, 2014-10-03) Veerabagu Suresh N; Agalya M; Subanya; Lavanya M; Rajesh K B
In this paper, we theoretically studied the role of the prism material in sensor design of SPR-based sensor. We analysed the performance of three prisms of different refractive indices coated with composites of Indium tin oxide and gold with different thickness values. We studied the reflection spectra under the angular interrogation mode and the performance are evaluated by employing two main parameters such as sensitivity and Full width Half Maximum (FWHM) of resonance curve. It is found that 10% of ITO hosted in metal matrix of gold gives the highest shift (8.14˚) in resonance angle and least FWHM (5.15˚) of the resonance curve for the film thickness of 50nm for the prism of np=1.456.
A COMPARATIVE STUDY ON THE PERFORMANCE OF SPR BASED CONVENTIONAL AND NANO-PLASMONIC FIBER OPTIC SENSORS
(Bannari Amman Institute of Technology, 2017-08) Subanya S; Pavithra D; Rajesh K B
The technique of Surface plasmon resonance has become a highly influential method for its chemical, bio-chemical and gas sensing applications due to its compactness, flexibility and reliability. A detailed analysis on the performance parameters of SPR based fiber optic sensors having different bimetallic configurations is performed. Two different sensor structures are considered for the study - One having the arrangement consisting of thin layers of Au/Ag with Pd and the other having an alloy layer formed of Au/Ag and Pd nanoparticles. The thickness of the metal layer, its dielectric constants and the thickness, length and refractive index of the sensing layer is properly chosen and the sensitivity evaluation is done. The attenuated total internal reflection method along with Krestchmann configuration has been used to analyze the sensor parameters. The effects of the metal structures considered and its thicknesses on the transmitted spectrum of the proposed sensor is analysed and the best configuration is predicted. The proposed optical model may find its application as a gas sensor.
EFFECT OF GRAPHENE LAYER ON CHALCOGENIDE GLASS PRISM BASED SPR SENSOR
(Chikkanna Government Arts College, Tirupur, 2017-01-19) Venkateswari P; Subanya S; Rajesh K B
It is observed that plasmonic structure based on (chalcogenide) sulfide glass Ge20Ga5Sb10S65 commonly known as 2S2G allows for a wide range of sensing applications in the infrared wavelength region. In this paper, we theoretically presents an improved sensitive surface plasmon resonance bio sensor using graphene layers on 2S2G prism. The light reflection coupled into a spr mode propagating along metal graphene interface on the 2S2G prism is calculated and compared to a conventional silver based spr bio sensor. This enhancement is due to the pi-stacking interaction between carbon based hexagonal structure of graphene and carbon based ring biomolecules which increases biomolecular adsorption in the graphene layer.
EFFECT OF GRAPHENE ON THE PERFORMANCE OF SPR BASED FIBER OPTIC SENSOR
(Chikkanna Government Arts College, Tirupur, 2017-01-19) Santhiya Devi S; Subanya S; Kasthuri R; Rajesh K B
Conventional SPR sensors makes use of a dielectric metal configuration which finds application in the visible and near infrared region. However, it is least sensitive to mid and far infrared region. To overcome the shortcoming, graphene ribbon array are employed. Due to its unique physical, chemical and optical properties, graphene finds its application in various photonic devices and sensors. Theoretical simulation on the effect of graphene on the performance of spr based fiber optic sensor has been done. The attenuated total internal reflection method along with Krestchmann configuration has been used to analyze the sensor parameters. The influence of the number of graphene layers on the various choice of metal having particular thickness was felt in the sensor performance. The proposed optical model suits best as a bio-sensor
ENGINEERING AXIALLY POLARIZED SUB-WAVELENGTH SCALE FOCAL STRUCTURES USING ANNULAR WALSH FILTER
(Springer Link, 2023) Umamageswari N; Thiruarul D; Lavanya M; William Charles J; Jaroszewicz; Rajesh K B
Based on vector diffraction theory, the tight focusing properties of radially polarized Bessel Gaussian beam (BGB), phase modulated by annular Walsh function filters and focused by a high NA parabolic mirror system are studied numerically. The annular Walsh filter derived from the annular Walsh functions forms a complete set of orthogonal phase filters that takes values of either 0 or π phase corresponding to + 1 or −1 over the domain specified by the inner and outer radii of the annulus. Numerical results show that by properly modulating the annular obstruction of Walsh filter and pupil to beam ratio of the input BGB, one can generate many novel focal patterns such as three-dimensional multiple sub-wavelength scale focal spot segments, optical needle, axial flat top profile, etc. We expect that such three-dimensional chain of focal structures is useful for nano-lithography, particle trapping and transportation, as well as confocal and STED microscopy, microstructure fabrication and so on.
EXCITATION OF SURFACE PLASMON ON GRAPHENE COATED METAL LAYER BY RADIALLY POLARIZED BESSEL GAUSSIAN BEAM
(Bharathiar University, 2013-02-01) Veerabagu Suresh N; Lavanya M; Subanya S; Rajesh K B
Rapid advance of nano structuring technologies offers new possibilities for flexible and low-cost fabrication of plasmonic components and devices. When a radially polarized Bessel Gaussian beam is focused onto a metal-dielectric interface, the entire beam is TM polarized with respect to the interface. Consequently surface plasmons can be excited at all directions. These surface plasmons will propagate to the geometric center, constructively interfere with each other and generate a strongly focused evanescent non diffracting Bessel beam. In this paper, we analysed the excitation of surface plasmon polaritons SPP by focusing a radially polarised Bessel Gaussian beam on a Chalcogenide glass plate and a gold layer coated with a thin layer of graphene. The graphene layer is used to enhance the adsorption of biomolecules. However the change in the intensity distribution of the generated surface plasmon owing to the presence of graphene layer is very important and is analysed numerically in this work.
GENERATION OF 1D ARRAY OF FOCAL SEGMENTS USING SPIRALLY POLARIZED BEAM AND COMPLEX PHASE FILTER
(Elsevier, 2022-05) Senthilkumar M; Udhayakumar M; Lavanya M; Mahadevan G; Rajesh K B; Jaroszewicz Z
A new approach for generating and tuning 1D array of sub wavelength scale electric and magnetic spot, hole, flattop and bubble profiled segments using tightly focused spirally polarized beam phase and amplitude modulated with suitable complex phase filter is proposed and investigated numerically using vector diffraction theory. Numerical result shows that by using a well optimized single Complex Phase Filter (CPF), one can generated and tune the geometry of the 1D chain of electric and magnetic field distribution from sub wavelength scale hole to spot and then to a chain of flattop profiled or bubble structure segments by properly tuning the spirallity of incident spirally polarized beam. These focal field distributions may find potential applications in laser direct writing and optical microscopy, as well as multiple-particle trapping, alignment, and acceleration along the optical axis.
GENERATION OF AXIALLY SPLITTED ULTRA-LONG MULTIPLE OPTICAL NEEDLES/OPTICAL TUBES USING GENERALIZED CYLINDRICAL VECTOR BESSEL GAUSSIAN BEAM PHASE MODULATED BY ANNULAR WALSH FUNCTION FILTER
(Springer Link, 2022-08-29) Thiruarul D; William Charles J; Lavanya M; Rajesh K B; Jaroszewicz Z
Based on vector diffraction theory and annular Walsh function filter, axially splitted ultra-long multiple optical needles/optical tubes of electric as well as magnetic field distributions are numerically generated by generalized cylindrical vector Bessel Gaussian beam phase modulated by annular Walsh function filter. This multiple optical structures can be conveniently tailored by properly tuning the initial phase of the Cylindrical vector beam (CVB) and Walsh order of the annular Walsh function filter. Furthermore, the effect of energy flux density (Poynting vector) as well as Spin angular momentum(SAM) distribution in the focal region are theoretically analyzed. We expect that such an axially splitted focal systems could be applicable in optical trapping and manipulation of multiple particles, optical super resolution microscopy etc.
GENERATION OF SUB-WAVELENGTH LONGITUDINAL MAGNETIZATION NEEDLE AND MULTIPLE LONGITUDINAL SPOTS USING CIRCULARLY POLARIZED BEAM THROUGH AN ANNULAR WALSH FUNCTION FILTER
(Springer Link, 2023-11-17) Thiruarul D; William Charles J; Lavanya M; Rajesh K B; Jaroszewicz Z
This numerical work demonstrates the possibility of generating sub wavelength scale magnetization spot of long focal depth and axially separated multiple magnetization segments using annular Walsh function filter. Numerical result calculated on the basis of vector diffraction theory (VDT) and Inverse Faraday Effect (IFE) shows upon suitably choosing the parameters of Walsh function filter such as order and annular obstruction, one can generate and tune the longitudinal magnetization needle and multiple magnetization spots in the focal plane for the input circularly polarized Bessel Gaussian beam. The generated sub wavelength magnetization structures are highly applicable in fields such as all-optical magnetic recording, multiple trapping and transportation of magnetic particles, magnetic resonance microscopy and multilayer ultra-high-density magnetic storage.
GENERATION OF SUPER LONG DARK CHANNEL USING ANNULAR MULTI-GAUSSIAN BEAM
(International Conference on Optics and Photonics 2015, International Society for Optics and Photonics, 2015-06-05) Lavanya M; Udhayakumar M; Shanmugapriya S; Rajesh K B
According to Vector diffraction theory, focusing properties of azimuthally polarized annular multi Gaussian beam through dielectric interface is numerically studied. It is observed that the presence of dielectric interface generates focal shift and the inclusion of annular obstruction at the aperture enhances the focal depth and minimized the focal hole size. By properly tuning the annular obstruction, a focal hole of FWHM 0.606 λ having super long focal depth of 3080λ is achieved. The focal depth of the dark channel achieved is found to be much larger than all the previously proposed methods.
GENERATION OF SUPER LONG DARK CHANNEL USING ANNULAR MULTI-GAUSSIAN BEAM
(SPIE Digital Library, 2015-06-15) Lavanya M; Udhayakumar M; Shanmugapriya S; Rajesh K B
According to Vector diffraction theory, focusing properties of azimuthally polarized annular multi Gaussian beam through dielectric interface is numerically studied. It is observed that the presence of dielectric interface generates focal shift and the inclusion of annular obstruction at the aperture enhances the focal depth and minimized the focal hole size. By properly tuning the annular obstruction, a focal hole of FWHM 0.606 λ having super long focal depth of 3080λ is achieved. The focal depth of the dark channel achieved is found to be much larger than all the previously proposed methods.
GENERATION OF ULTRA-LONG MULTIPLE OPTICAL TUBES USING ANNULAR WALSH FUNCTION FILTERS
(Springer, 2020-08-29) Thiruarul D; Rajesh K B; Lavanya M; Mahadevan G; Dhayalan, Velauthapillai; Jaroszewicz Z
The tight focusing properties of an azimuthally polarized Bessel Gaussian beam phase modulated by annular Walsh function filter is studied numerically by vector diffraction theory. It is observed that upon suitable optimization of order and annular obstruction ratio of an annular Walsh function filter, one can generate multiple sub wavelength scale optical tubes (optical holes) with super long focal depth. Such a focal system is usable for Nano-lithography, particle trapping and transportation, as well as confocal and STED microscopy, microstructure fabrication etc.
GRAPHENE BASED SPR BIOSENSOR FOR SENSITIVITY EVALUATION
(Chikkanna Govt. Arts College, Tiruppur, 2019-02-01) Kaviyarasi K; Abiramavalli T; Subanya S; Rajesh K B
In the recent years, the application of spr based fibre optic sensors have progressed very rapidly. Due to the increase in diseases and diagnotics, the urge for bio sensing applications have drawn the attention of researchers. A detailed numerical analysis on the performance parameter of an optical fibre based SPR sensors with Graphene layers over four different metals Pt/Au/Ag/Cu have been studied. Graphene not only helps in the adsorption of biomolecules due to pi-pi stacking interaction but also prevents metal oxidation. The thickness of the metal layer, its dielectric constants and the thickness, length and refractive index of the sensing layer is properly chosen and the sensitivity evaluation is done. The inclusion of Graphene layer is found to improve the sensitivity of the sensor. The attenuated total internal reflection method along with Krestchmann configuration has been employed for the evaluation. The effects of the metal structures considered and its thicknesses on the transmitted spectrum of the proposed sensor is analysed. Amongst the various chosen combinations, the proposed optimized Platinum Graphene coated SPR sensor demonstrates higher sensitivity than the previously reported spr sensors. The proposed configuration will surely be a promising candidate for high performance bio-sensing applications.
INVESTIGATION ON THE PERFORMANCE OF THE PRISM BASED SPR SENSOR WITH COMPOSITE OF INDIUM NITRATE AND GOLD
(Journal of Environmental Nanotechnology, 2014-12) Veerabagu Suresh N; Agalya M; Subanya S; Lavanya M; Rajesh K B
In this paper, we theoretically studied the role of the prism material in sensor design of SPR-based sensor. We analysed the performance of three prisms of different refractive indices coated with composites of Indium tin oxide and gold with different thickness values. We studied the reflection spectra under the angular interrogation mode and the performance are evaluated by employing two main parameters such as sensitivity and Full width Half Maximum (FWHM) of resonance curve. It is found that 10% of ITO hosted in metal matrix of gold gives the highest shift (8.14Ëš) in resonance angle and least FWHM (5.15Ëš) of the resonance curve for the film thickness of 50nm for the prism of np=1.456.
NUMERICAL SIMULATION OF SPR BASED FIBER OPTIC GAS SENSOR USING AN ALTERNATING DIELECTRIC MULTILAYER
(Chikkanna Government Arts College, Tirupur, 2017-01-19) Kasthuri R; Sathiyapriya D; Subanya S; Rajesh K B
The technique of Surface plasmon resonance has become a highly influential method for its chemical and bio-chemical sensor applications due to its compactness and reliability. Surface plasmon resonance based fiber optic sensor with an alternating dielectric multilayer system is theoretically studied in detail. The dielectric system is constructed with alternate silica and titanium oxide layers sandwiched between the metal of study. Besides prevention of metallic layer from oxidation, it also enhances the sensitivity, tunability of the resonance wavelength region, bio-compatibility and capability of gas sensing. The effect of various design attributes on the sensitivity and detection accuracy of the sensor is studied for three different metal layers.. Based on the study, a new optical model of a fiber optic spr gas sensor is proposed.
NUMERICAL SIMULATION ON THE PERFORMANCE OF SPR BASED FIBER OPTIC SENSOR USING NANOCOMPOSITES
(Chikkanna Govt. Arts College, Tiruppur, 2019-02-01) Abiramavalli T; Kaviyarasi K; Subanya S; Rajesh K B
In the last few decades, Surface Plasmon Resonance technique has become highly influential for its chemical, bio-chemical and gas sensing applications due to its compactness, flexibility and reliability. Transparent conducting oxide like In2O3 are of immense interest due to their good electrical conductivity property and high transparency in the visible and infra red region. A study on the performance of spr based fiber optic sensor with nanocomposites has been carried out numerically and investigated. Nanocomposites comprising of Co and Ni nanoparticles with their varying volume fractions embedded in the host dielectric matrices of Indium Oxide are considered for the study. The metal nanoparticles exhibit tremendous optical properties originating from the surface plasmons and hence show better sensing performance than materials in the macro or large scales. By varying the thickness of the nanocomposite for various volume fractions, the performance parameters such as FWHM, sensitivity and Q-factor of the sensor were studied and analyzed. The sensitivity of Ni/In2O3 nanocomposites based sensor shows better performance for all thicknesses with any volume fraction compared to Co/In2O3 nanocomposites. It is observed that the sensitivity of the sensor increases with increase in both thickness of the nanocomposites and the volume fraction of metal nanoparticles. The usage of Co and Ni in the place of noble metals has curtailed the cost of the spr sensor.
PERFORMANCE ANALYSIS OF GRAPHENE BASED SPR SENSORS FOR BIO SENSING APPLICATIONS
(IIT Delhi, 2018-12-13) Subanya S; Rajesh K B
For the past three and more decades, the application of spr based fibre optic sensors have progressed very rapidly. Due to the increase in diseases and diagnotics, the struggle for existence of human life increases and hence the urge for bio sensing applications have drawn the attention of researchers. Numerical analysis on the performance parameter of an optical fibre based SPR sensors with Graphene layers over four different nobel metals have been studied. Graphene which is a biological resistance element not only helps in the adsorption of biomolecules due to pi-pi stacking interaction but also prevents metal oxidation. The paramters of the sensor such as the thickness of the metal layer, its dielectric constants, length and refractive index of the sensing layer is properly chosen and the sensitivity evaluation is done. The presence of the Graphene layer is found to enhance the sensitivity of the sensor. The attenuated total internal reflection method along with Krestchmann configuration has been employed for the evaluation. The effects of the metal structures considered and its thicknesses on the transmitted spectrum of the proposed sensor is analysed. Amongst the various chosen combinations, the proposed optimized Platinum Graphene coated SPR sensor demonstrates higher sensitivity than the previously reported spr sensors. The proposed configuration will surely be a promising candidate for high performance bio-sensing applications.
SENSITIVITY ENHANCEMENT OF A SURFACE PLASMON RESONANCE BASED FIBER OPTIC REFRACTIVE INDEX SENSOR USING UTILIZING AN ADDITIONAL LAYER OF OXIDE
(Chikkanna Government Arts College, Tirupur, 2017-01-19) Alagu Vibisha G; Subanya S; Rajesh K B
Surface Plasmon Resonance base fiber optic sensor with bi layers of Pt- TiO2 is theoretically analysed. The Pt layer over TiO2 layer has been shown to improve the sensitivity of SPR sensor, The sensitivity of the proposed sensor enhances linearly with the increase in the refractive index of the sensing medium for all thicknesses of Pt layers, with increase in TiO2 layer thickness. SPR based fiber optic sensor with bi layers of 50 nm Pt-200nm TiO2 displays the highest sensitivity of 18000 nm/RIU.
SURFACE PLASMON RESONANCE BASED FIBRE OPTIC SENSORS FOR SENSITIVITY EVALUATION
(PSGR Krishnammal College for Women, 2019-01-21) Abiramavalli T; Kaviyarasi K; Subanya S; Rajesh K B
The technique of Surface plasmon resonance has become a highly influential method for its chemical, bio-chemical and gas sensing applications due to its compactness, flexibility and reliability. Recent reports convey that Surface Plasmon Resonance has also been involved in the energy conversion of solar energy harvesting with the application of metamaterials. Surface Plasmon resonance imaging involves the detection of material properties like density, temperature, concentration, refractive index measurement under various environmental conditions. A detailed numerical analysis on the performance parameter of an optical fibre based SPR sensors with Graphene layers over four different metals Pt/Au/Ag/Cu have been studied. The inclusion of Graphene layer is found to improve the sensitivity of the sensor. The thickness of the metal layer, its dielectric constants and the thickness, length and refractive index of the sensing layer is properly chosen and the sensitivity evaluation is done. The attenuated total internal reflection method along with Krestchmann configuration has been employed for the evaluation. The effects of the metal structures considered and its thicknesses on the transmitted spectrum of the proposed sensor is analysed. Amongst the various chosen combinations, the proposed optimized Platinum Graphene coated SPR sensor shows greater sensitivity than the previously reported spr sensors.
THEORETICAL ANALYSIS OF SPR CHARACTERISTICS OF IRIDIUM
(Chikkanna Government Arts College, Tirupur, 2017-01-19) Mohanapriya S; Subanya S; Kasthuri R; Rajesh K B
The technology and applications of optical fiber have progressed very rapidly in the recent years. A detailed theoretical analysis on the performance of single and bimetal iridium layer coated on a core of an optical fiber. By varying the structure of the iridium as thin film, nanoparticle and grating, the performance of the spr based fiber optic sensor is studied and compared in detail. To study the performance of the sensor, we calculated the sensitivity, Reflection coefficient, Q factor and FWHM using Iridium with other spr active metals. Interestingly, as the thickness of the iridium layer increases, dominance of inverted surface plasmon resonance character of iridium was also observed and analyzed. At specific conditions, iridium exhibits normal as well as inverted spr characteristics. The proposed sensor finds application in various fields.