This book focuses on advanced optical properties and applications of tellurite glasses and tellurite glasses doped with rare-earth nanoparticles. The initial chapter presents the current state of the art in tellurite glass development, focusing on those compositions doped with nanoparticles based on rare-earth elements such as neodymium and erbium. The book then discusses various linear and nonlinear optical properties (e.g., refractive index, absorption, optical susceptibility) of these glasses in the visible and ultraviolet spectral regions. Finally, it looks at a selection of recent technological applications of doped tellurite glasses, such as highly efficient laser glass, novel temperature sensors, and advanced optical fiber material. Featuring comprehensive and up-to-date data sets, along with a topical discussion of promising new areas of application, this book is particularly suitable for researchers and industry professionals working in the field of glass manufacturing for optics and laser applications.