Plasmonics stems from the surface charge density oscillations at metal-dielectric interface, leading to extremely strong light-matter interactions. In the past few decades, plasmonics has become one of the most favorite fields/techniques in realizing high-performance photonic devices. For this purpose, different new concepts, such as exploration of different radiation frequency regions, two-dimensional materials/heterostructures, and different types of substrates for the excitation of plasmons have been investigated for plasmonics-based sensors and detectors. This book focuses on the recent and advanced works on optical sensors and detectors utilizing plasmonic techniques for opto-electronic applications. The book is unique as it describes both sensors and detectors based on plasmonics and their practical applications in a single book, a feature not found in any book so far.