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Prabakaran K.,Mahendra Arts and Science College Autonomous | Rajesh K.B.,Government of Tamilnadu | Chandrasekaran R.,Government of Tamilnadu | Sarasvathi R.C.,Government of Tamilnadu
Journal of Optics (India) | Year: 2015

We propose a new approach for generating multiple focal spots segment of sub wavelength size, by tight focusing of phase modulated double ring shaped radially polarized beam. The focusing properties are investigated theoretically by vector diffraction theory. We proposed to design of binary phase plate (BPP) which can tune the phase of the incident RTEM11 * mode radially polarized Laguerre –Gaussian beams (R-TEM11*) beam in such way to generate a focal segment with four and three numbers of focal spots repectively. We also observed that by properly tuning the pupil to beam ratio(β) of the incident R-TEM11* beam, the generated four or three focal spot segment can be tuned to a focal segment of two focal spot. © 2015, The Optical Society of India.

Chandrasekaran R.,Government of Tamilnadu | Prabakaran K.,Mahendra Arts and Science College Autonomous | Rajesh K.B.,Government of Tamilnadu
Optical and Quantum Electronics | Year: 2016

We investigated the focusing properties of a cylindrically polarized annular multi Gaussian beam tightly focused with a high NA lens and a complex phase filter. It is observed that a properly designed complex phase filter can generate multiple focal spot and focal hole segments along optical axis its useful for the manipulation of multiple optical traps of low and high refractive index particles. © 2015, The Author(s).

Sundaram C.M.,Periyar University | Prabakaran K.,Mahendra Arts and Science College Autonomous | Anbarasan P.M.,Periyar University | Rajesh K.B.,Government of Tamilnadu | Musthafa A.M.,Royal University
Chinese Physics Letters | Year: 2016

The intensity distribution in the focal region of a high-NA lens for the incident azimuthally polarized multi Gaussian beam transmitted through a multi belt spiral phase hologram is studied on the basis of the vector diffraction theory. Here we report a new method used to generate a needle of transversely polarized light beam with sub diffraction beam size of 0.366λ that propagates without divergence over a long distance of about 22λ in free space. We also expect that such a light needle of transversely polarized beam may find its applications in utilizing optical materials or instruments responsive to the transversal field only.

Chandrasekaran R.,Government of Tamilnadu | Prabakaran K.,Mahendra Arts and Science College Autonomous | Rajesh K.B.,Government of Tamilnadu | Mohamed Musthafa A.,Royal University | Ravi V.,Government of Tamilnadu
Optik | Year: 2016

Focusing properties of cylindrically polarized annular multi gaussian beam with high numerical aperture lens system is investigated theoretically by vector diffraction theory. Results show that intensity distribution in focal region can be tailored considerably by appropriately adjusting the polarization angle. Peak-centered, donut and flattop focal shapes with extended focal depth, potentially useful in optical tweezers, material processing and laser printing can be obtained using this technique. © 2016 Elsevier GmbH. All rights reserved.

Praburaman L.,Chonbuk National University | Park J.-H.,Chonbuk National University | Govarthanan M.,Chonbuk National University | Selvankumar T.,Mahendra Arts and Science College Autonomous | And 5 more authors.
Chemosphere | Year: 2015

The study was aimed to evaluate the potential of organic formulation, panchakavya, for enhancing the biological leaching of Pb and Cu in contaminated mine soil. Response surface methodology based Box-Behnken design was used to optimize the variables such as incubation time, panchakavya concentration, and agitation rate. The maximum bioleaching (Pb=64% and Cu=49%) was observed after 54h of incubation with 10mL panchakavya at 120rpm. Statistics-based contour and three-dimensional plots were generated to understand the relationship between Pb and Cu bioleaching and variables. High-performance liquid chromatography analysis showed the presence of lactic (25.88mgg-1), citric (0.14mgg-1), succinic (0.14mgg-1), malic (0.66mgg-1), and acetic (0.44mgg-1) acids in panchakavya, which may have a vital role in the removal of metals from the contaminated soil. Soil fraction studies indicate a significant increase of Pb (45%) in the exchangeable fraction of panchakavya-treated soil. XRD studies confirmed the role of panchakavya induced calcite and other minerals in the precipitation of metal ions. A significant increase in the enzyme activities of phosphatase, dehydrogenase, urease, amylase, invertase, and cellulase were observed in the panchakavya-treated soil. © 2015 Elsevier Ltd.

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