The word ‘photonics’ is derived from the Greek word “photos” meaning light and Electronics; Photonics is the technology of generating and harnessing light and other forms of radiant energy whose quantum unit is a photon. The science include light emission, transmission, deflection, amplification, detection by optical components and instruments, lasers and other light sources, fibre optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems etc.
In brief photonics is the technology of mastering light in areas where electronics or electrons are applied. Theoretically, almost any physical or environmental parameter can be measured using light and this is core principle on which photonics works with basic unit as a photon instead of a conventional electron.
Applications of photonics are telecommunications, information processing, lighting, metrology, spectroscopy, holography, medicine (surgery, vision correction, endoscopy, health monitoring), military technology, laser material processing, visual art, biophotonics, agriculture, and robotics. Economically important applications for semiconductor photonic devices include optical data recording, fibre optic telecommunications, laser printing (based on xerography), displays, and optical pumping of high-power lasers.