Browsing by Author "Lavanya M"

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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.
ENERGY FLUX DENSITY FOR HIGHER-ORDER CYLINDRICAL VECTOR VORTEX BEAM TIGHTLY FOCUSED THROUGH A DIELECTRIC INTERFACE
(Springer India, 2021) Lavanya M; Thiruarul D; Rajesh KB; Mahadevan G; Dhayalan, Velauthapillai; Jaroszewicz Z
Energy flux density for higher-order cylindrical vector vortex (HCVV) beam focused through a dielectric interface is analyzed numerically based on vector diffraction theory. Numerical results shows variation in the direction of the energy flux or Poynting vector distribution both in transverse and longitudinal plane upon suitably tuning the topological charge and polarization order of HCVV beam. We also note that the strong reverse flow of energy occur at the centre of the focal plane for certain values of the topological charge and polarization order. These results may find potential applications in optical trapping and optical manipulations.
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.
ENGINEERING AXIALLY POLARIZED SUB-WAVELENGTH SCALE FOCAL STRUCTURES USING ANNULAR WALSH FILTER
(SpringerLink, 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.
FOCUSING PROPERTIES OF SPIRALLY POLARIZED ANNULAR MULTI GAUSSIAN BEAM BY HIGH NA LENS
(International Journal of Advanced Science and Engineering, 2022-08-01) Senthilkumar M; Rajesh K; Udhayakumar M; Prabakaran K; Lavanya M
Focusing properties of spirally polarized annular multi Gaussian beam by High NA Lens are investigated theoretically by vector diffraction theory. Results show that the optical intensity in focal region of spirally polarized annular multi Gaussian beam can be altered considerably by the beam order and spiral parameter. Spiral parameter can induce focal pattern change in axial direction remarkably and many novel focal patterns including optical bubbles, focal hole and focal spots of long focal depth and axially separated focal spots and flattop profile are evolved. We expect such a tunable focal patterns are useful for optical manipulation of micro particles.
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 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 AXIAL MULTI FOCI PATTERN
(Research Square, 2022-10-14) Thiruarul D; William Charles J; Lavanya M; Rajesh K.B; Jaroszewicz Z
Axially splitted multi foci(AMF) are numerically generated by tight focusing of higher order cylindrical vector beam(HCVB) through an annular Walsh filter .Here we report that by properly manipulating the parameters of HCVB such as initial phase(φ0 ),topological charge (m), polarization rotation angle or azimuthal index (a) and suitably phase modulated with a Walsh function filter of fixed orders (n) and annular obstruction (ε),onecan generate axially polarized multiple spots,transversely polarized multiple holes,transversely polarized multi spots,axially and transversely polarized multi holes with extended central annular region.These distributions may be useful for multiple optical trapping and axial superresolution microscopy.
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 AXIALLY SPLITTED ULTRA-LONG MULTIPLE OPTICAL NEEDLES/OPTICAL TUBES USING GENERALIZED CYLINDRICAL VECTOR BESSEL GAUSSIAN BEAM PHASE MODULATED BY ANNULAR WALSH FUNCTION FILTER
(SpringerLink, 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 MULTIPLE FOCAL PATTERN VIA PHASE MODULATED RADIAL AND AZIMUTHAL VARIANT VECTOR BEAM
(Springer, 2023-03-07) Thiruarul D; William Charles J; Lavanya M; Rajesh K.B; Jaroszewicz Z
The multiple focal patterns such as longitudinally/transversely polarized multiple focal spots/holes, longitudinally/transversely polarized annular dark multiple spots with petal shapes are in high demand for applications such as multiple optical trapping and manipulating, light-sheet fluorescence microscopy and optical lithography. This article numerically demonstrated the possibility of achieving the above task by subjecting phase modulation of radial and azimuthal variant vector beam through suitable annular Walsh function filter. Here it is demonstrated that the inherited self similarity properties of annular Walsh function and the flexibility of tuning the radial and azimuthal index of input beam is a state of art in landscaping multiple focal segment of desirable spatial and polarization distribution.
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.
INTEGRATING DYNAMIC ARCHITECTURE WITH DISTRIBUTED MOBILITY MANAGEMENT TO OPTIMIZE ROUTE IN NEXT GENERATION INTERNET PROTOCOL MOBILITY
(Indian Society for Education and Environment, 2015-05) Senthilkumar Mathi; Lavanya M; Priyanka R
Increasing population of mobile users has lead to the demand of higher mobility support. Many protocols have been standardized for mobility management such as Mobile Internet Protocol version 6, hierarchical mobile IPv6 and proxy mobile IPv6 and so on. The predominantly used approach in the existing mobile networks is the centralized mobility management. In this, the messages transferred between mobile node and correspondent node must pass through each level due to the hierarchical architecture. When a mobile network is implemented with the centralized architecture, the messages are routed to the MN irrespective of its location using mobile IP for continuing services during the handover. But this approach is susceptible to issues such as single point of failure, non-optimized routes, latency issues, wastage of resources and security threats which affect the performance and scalability, demanding a flatter architecture with an efficient mechanism to face the traffic overload from the mobile users. Hence, the paper proposes a new scheme to form a flatter architecture by distributing the mobility management functionalities as distributed access point at the access level. The resistance against security threat such as man-in-the-middle attack, replay attack and false binding update attack has been achieved. Finally, numerical results show that the proposed scheme provides significant reduction in signaling cost and improves efficiency in route optimization
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.
A SURVEY ON AGRICULTURE AND GREENHOUSE MONITORING USING IOT
(Sciencepubco, 2018) Lavanya M; Sujatha, Srinivasan
Internet of things (IoT) is connecting physical objects around us; those physical objects can be monitored with the help of sensors. A sensor is a device, which is used to sense physical property of an element, any events or any changes present in the environment and send the in-formation to other electronic device, frequently a computer. Many research are made on those sensor enabled IoT system to provide intelli-gent and smart services, towards smart greenhouse and smart agriculture .This paper will explore various existing IoT based agriculture and greenhouse system according to their deployment with an intension of identifying how it can be improved in future using IoT, WSN and a very recent scenario of using cloud computing.
TIGHT FOCUSING PROPERTIES OF AZIMUTHALLY POLARIZED PAIR OF VORTEX BEAMS THROUGH A DIELECTRIC INTERFACE
(Chinese Physics letters, Iopscience.iop.org, 2017-07-17) Janet C A P; Lavanya M; Rajesh K B; Udhayakumar M; Jaroszewicz Z; Velauthapillai D
Tight focusing properties of an azimuthally polarized Gaussian beam with a pair of vortices through a dielectric interface is theoretically investigated by vector diffraction theory. For the incident beam with a pair of vortices of opposite topological charges, the vortices move toward each other, annihilate and revive in the vicinity of focal plane, which results in the generation of many novel focal patterns. The usable focal structures generated through the tight focusing of the double-vortex beams may find applications in micro-particle trapping, manipulation, and material processing, etc.