This book presents the state-of-the-art coverage of optical materials and their application in various areas. The contents range from basic principles to quantum cutting luminescent materials, advances in plasmonic and photonic substrate-coupled fluorescence, lanthanide doped materials for optical applications, thermoluminescence and optical material for sensing radioactive elements. It also discusses synthesis, characterization and properties of optical materials including nanomaterials, luminescent nanomaterials for anti-counterfeiting, carbon materials-based nanoscale optics and plasmonics, optoelectronics applications of two dimensional materials and applications of lanthanide ion-doped phosphors. This book is of immense value to those in academia and industry working in the areas of material science, especially optical materials.