s. DeepaIndian Institute of Technology Delhi | IIT Delhi · Department of Physics
Doctor of Philosophy
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Citations since 2017
9 Research Items
We discuss a technique to invert the helicity of generic C points and generate its orthogonal state of polarization in a single step through a fork grating (FG). It is experimentally demonstrated that the beam in each of its diffraction orders possesses a degenerate C point index state. The diffraction phenomenon reported is helicity-dependent, in...
The superposition of spin and orbital angular momentum states of light generates polarization singularities. By perturbing and disintegrating their component orbital angular momentum (OAM) states, the polarization singularity indices can be determined. The spatially varying polarization distribution of these beams possesses information about the he...
We investigate the peculiar diffraction behavior of the vector fields on passing through a diamond shaped aperture. The higher-order vector fields embedded with V-point singularity are generated using a rectangular path Sagnac interferometer. It is witnessed that the order (magnitude of Poincare-Hopf index) of the vector field singularity can be di...
Stokes phase is the phase difference between orthogonal component states in the decomposition of any polarization state. Phase singularities in the Stokes phase distribution are Stokes singularities of an inhomogeneous polarization distribution. Under circular decomposition, Stokes phase distribution (ϕ12) represents polarization azimuth (γ) distri...
In this paper, we report the morphological transformations of vector-field singularities (V-points) under symmetric and asymmetric perturbation using a diamond-shaped diffracting aperture. The number of null intensity points in the diffraction pattern depicts the magnitude of the polarization singularity index. Also, under symmetric perturbation, a...
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
In this article we show that diffraction segregates the polarization singularities according to their handedness. Polarization singularities are superpositions of left and right handed circular polarization vortex states. In the superposition, the component states possess different orbital angular momenta depending on the type of the singularity. A...
In singular beams, topological charge is conserved during diffraction. Like scalar field diffraction, in vector field diffraction also, there are conserved quantities. A diffracting V-point disintegrates into a number of C-points of the same polarity in which the polarization singularity index is conserved. In this Letter, we show for the first tim...
High-density optical data storage is a current field gaining importance where research work is done in abundance to bring about holographic CDs to light. Dye-doped gelatin films are promising candidates as recording materials for holographic data storage because of the ease of preparation and low cost. In this report we suggest some acid red dyes a...
Eosin dye based poly(methacrylates) with variation in the number of methylene spacers have been prepared by free radical polymerization process. The utility of the polymers for high-density optical data storage using holography has been studied by grating formation with the 514.5 nm line of the Argon ion laser as source. The influence of various pa...
Singularlites that exist in the parameters used to define polarization of light.