Photonics is a multidisciplinary subject that combines electronics and optical technologies. Primarily intended for the undergraduate students of Physics, this book explains the fundamental aspects of Photonics, in detail. Starting from the basics, the book elaborately discusses the advanced topics, specifically highlighting the research studies done in the field. The concepts are theoretically explained and mathematically treated to help the students in understanding the concepts skillfully. The book explains the phenomena like the particle properties of light, the potential of creating signal processing device technologies using photons, the practical application of optics, and an analogy to electronics. The topics on radiometry, optical processes in semiconductors, light emitting diodes, photodetectors, and solar cells; fibre optics; modulation; holography; lasers; non-linear optics; integrated optics; and display devices are also dealt with, in detail. The topics are well-supported with the neatly labelled figures and illustrations. The solved examples, included in every chapter, give an analytical insight to the subject.