This book focuses on the fundamentals, technologies and properties of ion irradiation of dielectric materials (e.g. glasses, crystals) with regard to various photonic applications. It introduces readers to diverse ion-beam techniques for the fabrication and modification of micron- or nanoscale photonic structures, including optical waveguides, photonic crystals, and nanoparticle (nano-spheres and nano-rods) systems, and presents state-of-the-art advances in this multi-disciplinary research field, demonstrating the unique capabilities of ion-beam technologies in optical dielectric materials processing. The book discusses in detail the properties of ion-beam processed waveguides, as well as the modification of dielectrics for photonic applications, such as electro-optic modulation, nonlinear frequency conversion, waveguide amplification and lasing. It also explores synthesis and the correlated optical effects of nanoparticles by ion beams, and features examples of successful micro- and nano-photonic devices. Given its breadth of coverage, the book will particularly appeal to readers interested in ion-beam technology, materials science, and integrated optics.