"I have about ten years of research experience in photovoltaics, nanoscience, optics, and plasmonics. I was part of various individual and group research projects in prestigious institutes like IIT Delhi, IISc Bangalore, IISER Pune, and NIT Calicut. Currently, I am part of PSG Institute of Advanced Studies, Coimbatore. My research findings have been reported in peer-reviewed international journals and prestigious conferences. The highlights of major research projects are discussed here."
Plasmon Enhanced Optical Nonlinearity of Au-WS2 Nanohybrids
Nonlinear optical properties of Au-WS2 nanohybrids were studied using the open aperture Z-scan technique with nanosecond laser pulses of wavelength 532 nm, which lie in the plasmonic band of Au NPs (480–550 nm) and B-excitonic transition range of WS2 nanosheets (520–535 nm). Au–WS2 nanohybrids exhibited an enhanced nonlinear absorption and optical limiting activity with an effective nonlinear absorption coefficient of 182 cm/GW at an on-axis input intensity of 0.14 GW/cm2, which is 3.87 times higher than that of bare WS2 nanosheets.
Linearly Polarized Emission from One Dimensional Organic Semiconductor Microstructures
Linearly polarized emission was observed from a crystalline 1D PTCDI-C8 microstructure. Rotating microscopy imaging of this structure under crossed polarization was performed for the investigation of polarized emission. The anisotropy birefringence was maximum only when the 1D microstructure was aligned 45 degrees to the direction of the polarizer, and it was minimum when aligned parallel to the polarizer.
Nonlinear Optical Properties of Few layer Transition Metal Dichalcogenide Nanoflakes
Open aperture Z scan analysis of both the MoS2 and WS2 nanoflakes using 532 nm nanosecond laser pulses reveals strong nonlinear absorption activity with effective nonlinear absorption coefficient of 120 cm/GW and 180 cm/GW, respectively, which was attributed to the combined contributions of ground, singlet excited and triplet excited state absorption. Optical limiting threshold values of MoS2 and WS2 nanoflakes were obtained as ~ 1.96 J/cm2 and 0.88 J/cm2, respectively, which is better than many of the reported values.
Plasmon Assisted Light Propagation in Chemically Synthesized Silver Nanowires
Around 15-micrometer length Ag nanowires were chemically synthesized using the Polyole method. The waveguiding capability of these nanowires was investigated by irradiating the nanowire at one end using a laser beam. The surface plasmon polariton-assisted light propagation of more than 15 micrometers was successfully demonstrated using this experiment. These results suggest the subwavelength light propagation ability of synthesized Ag nanowires.
Plasmonic Nano-architectures for Highly Sensitive Surface Enhanced Raman Scattering Applications
The surface roughened Ag nanospheres and nanowires were chemically synthesized for highly sensitive surface-enhanced Raman scattering applications. The large numbers of plasmonic ‘hot spots' on the surface of nanostructures significantly increased the Raman scattering signals of analyte molecules. This proposed technique has the capability of performing less than nanomolar concentrated/single molecule detection of analyte molecules.