Fundamentals of Optical Transitions of Rare-earths and Doped Glasses for Photonic Applications

Abstract: Following the development of optical fiber networks of low-loss silica fiber and needs of large-capacity telecommunication by the wavelength-division multiplexing (WDM) technology, various kind of fiber amplifiers were invented for different wavelength regions from O- to U- bands. Erbium, praseodymium and thulium were three representative active center ions, where the f-f luminescent transitions at each key band require different properties for their host glasses, which are strongly correlated with the 4f energy level structures.
After the invention of InGaN-based blue LED, the white LED lamps were invented in the very late 1990s, which has also driven the revolution in the lighting technologies in this 21st century. Most of LED lamps are a phosphor-converting type, in which the 5d-4f transitions of Ce3+ or Eu2+ doped phosphors play critical role, which can achieve broad and widely tunable luminescence in the whole visible range with large cross section.
This talk will review the development histories of rare-earth doped materials for these two different technologies on the basis of required properties and design concepts as well as their future prospects.

Setsuhisa Tanabe is a Professor of Material Chemistry at Graduate School of Human and Environmental Studies, Kyoto University, Japan. He is the author of 270+ original papers, 25+ book chapters, and 40+ review papers on rare-earth doped luminescent materials for upconversion lasers, optical fiber amplifier for telecommunication, LED phosphors and persistent phosphors. He has served as a plenary, keynote or invited speaker at 140+ international conferences and at 200+ domestic meetings & seminars. Based on his scientific contributions on photonic glasses, he was awarded W.E.S. Turner Award from ICG in 2012 and Varshneya Frontier of Glass Science Award from American Ceramic Society, ACerS in 2018 as well as several academic awards from Ceramic Society of Japan, Chemical Society of Japan, Rare-Earth Society of Japan and so on. He is a Fellow of SPIE and ACerS. He now serves as a Main Editor of Journal of Luminescence and the Chair of Japanese committee of UN International Year of Glass 2022.