Browsing by Author "Senthilkumar M"

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    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.
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    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.
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    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.
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    REPELLENCY PROPERTY OF CERTAIN ESSENTIAL OILS AGAINST TWO-SPOTTED SPIDER MITE, TETRANYCHUS URTICAE (KOCH) ON CLUSTERBEAN [CYAMOPSIS TETRAGONOLOBA (L.) TAUB
    (Agri-Bio-Publishers, 2020) Sathyaseelan V; Senthilkumar M; Pazhanisamy M; Baskaran V
    It is obvious that the quality and quantity of clusterbean were drastically reduced by various insect and pests. The study was carried out to evaluate the bioefficacy of various essential oils on the repellency property against two spotted spider mite on clusterbean. Treatments included the Eucalyptus oil, Ocimum oil, Lavendula oil, Mentha oil, Rosemarinus oil, Cymbopogon oil, Syzygium oil and untreated check for its efficacy. The maximum repellency was recorded in case of Eucalyptus oil (82.42%) and Ocimum oil (79.26%) followed by Rosemarinus oil (76.81%). The Mentha oil and Cymbopogon oil showed similar results, whereas the Syzygium oil (68.14%) recorded a moderate repellency against mite. The least repellency was recorded in Lavendula oil (52.87%) against two-spotted spider mite after 48 h of release.