Browsing by Author "Udhayakumar M"

Filter results by typing the first few letters
Now showing 1 - 7 of 7
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    TIGHT FOCUSING PROPERTIES OF PHASE MODULATED AZIMUTHALLY POLARIZED DOUGHNUT GAUSSIAN VORTEX BEAM BY HIGH NA PARABOLIC MIRROR
    (Materials Today Proceedings, Elsevier, 2019-08-10) Umamageswari N; Lavanya M; Udhayakumar M; Rajesh K B; Zaroszewicz Z
    The intensity distribution in the focal region of a high NA parabolic mirror for the incident azimuthally polarized doughnut Gaussian vortex beam (DGVB) transmitted through a multi belt complex phase filter (MBCF) is studied using vector diffraction theory. By properly designing the phase of the incident beam using MBCF and by tuning the beam parameters of a DGVB, it is possible to switch the focal spot with sub wavelength dimension and long focal depth in to multiple focal spots suitable for particle acceleration, atom optical experiments, and near-field scanning optical microscopy