Departmental Seminar

Down and upconversion in lanthanides for photonic devices

Professor C.K. Jayasankar
Department of Physics, Sri Venkateswara University, Tirupati, India

Lanthanide (Ln3+)-doped glasses, glass-ceramics and phosphors have been used for a variety of technological applications such as bio-labels, waveguide lasers, solar cells, laser diodes, etc., due to their characteristic features such as intense fluorescence with high emission cross-section and longer lifetimes, ability to tune the emission from infrared to visible regions by exploiting the down-conversion, up-conversion, cross-relaxation and energy transfer process. In spite of remarkable progress has been made, unfortunately, till date, there is no systematic relation between composition of the host matrix/concentration of Ln3+ ion and spectroscopic properties. The reason may be due to errors involved both in experimental and theoretical analyses. To resolve these issues, our group has been prepared variety of Ln3+ based systems and characterized their spectroscopic properties systematically.The detailed analysis such as intensity parameters, excited state lifetimes, stimulated emission cross-sections, gain band width, figure of merit, chromaticity color coordinates, multipolar interactions, energy transfer parameters, etc., for variety of Ln3+: matrices have been estimated besides exploring the development of photonic devices.

Dr. Chalicheemalapalli Kulala Jayasankar has made outstanding contributions on the preparation, characterization and optimization of a variety of lanthanide-doped optical quality glasses/nano-glass ceramics and nanocrystalline materials for various applications like the development of lasers, optical fiber amplifiers, sensors, biolabels, W-LEDs and buried waveguides. The Nd:glasses that he developed showed far better characteristics than commercially available laser glasses. The research activities of Prof. Jayasankar are of both fundamental as well as applied in nature. These research activities have been supported/collaborated by a wide variety of Government and industrial organizations both from India and abroad (Germany, UK, Italy, Spain, Mexico, Thailand and Portugal). He has published 290 papers in peer-reviewed International Journals with over 8175 citations, h-index 52 and i10-index 179 according to Google Scholar. He guided 26 PhD and 10 MPhil students. A recent scientometrics analysis of rare earths research in India published in Current Science (110, 1184-7(2016)) lists Prof. Jayasankar as one of the most prolific Indian authors in field of rare earths research in the order of z-index.

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