• P Kumar

      Articles written in Pramana – Journal of Physics

    • X-ray photoelectron spectroscopy, high-resolution X-ray diffraction and refractive index analyses of Ti-doped lithium niobate (Ti:LiNbO3) nonlinear optical single crystal

      P Kumar S Moorthy Babu S Perero Rajamaniccam L Sai I Bhaumik S Ganesamoorthy A K Karnal

      More Details Abstract Fulltext PDF

      Congruent LiNbO3 single crystals with Ti ion dopants (2 and 5 mol%) were successfully grown by Czochralski technique in the automatic diameter control facility. As-grown crystal boules were oriented into (0 0 1) direction cut and optically polished for all measurements. Influence of Ti-ion incorporation into LiNbO3 was studied by core level XPS analysis. Powder X-ray diffraction studies were carried out on doped lithium niobate for phase identification. High-resolution X-ray diffraction technique was used to study the crystalline quality through full-width at half-maximum values. The refractive index values are more for doped samples than for pure sample as determined by prism coupling technique with different laser sources.

    • Development of evanescent wave absorbance-based fibre-optic biosensor

      T Kundu V V R Sai R Dutta S Titas P Kumar S Mukherjee

      More Details Abstract Fulltext PDF

      Development of chemical and biochemical sensors is the current need of the society. In this report, we present our investigation on the development of a label-free fibre-optic biosensor based on evanescent wave absorbance to detect the presence of analytes such as bacteria, virus and some clinically important proteins. A simple UV-LED (280 nm) and photodetector combination along with a fibre probe was used for developing cost-effective, user-friendly and field applicable device. To improve the sensitivity of the detection technique, the probe design was modified and the U-bent probe was fabricated by simple procedure. Further, to overcome the problems for using UV light source in the fibre, the localized surface plasmon resonance of noble metal nanoparticles at visible wavelength was exploited as a sensing medium for the biochemical reactions. Our systematic studies in this regard presented in this communication may bring the excitement for developing the waterborne pathogen detection device for house-hold as well as field applications.

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