Optics is the branch of physics that deals with visible light and other electromagnetic waves. Light has a “dual personality” since it sometimes behaves like a wave and other times like corpuscles or discrete packets of energy called photons. This is known as its “wave-corpuscle duality”. Just as the term electronics was derived from electron, in recent years the term Photonics has been coined from photon. Although the terms optics and photonics are often used indiscriminately, the latter is sometimes used to underline the corpuscular nature of light. The number of devices and systems that operate with light is constantly increasing and the many different fields in which these are used are referred to as “light-based technologies”.
Nowadays optics and its technologies have spread from universities and research laboratories to form part of our daily life. They may be found in hospitals and all types of industries. They are used to correct and improve our vision. With the help of optic fibres our telephone conversations are relayed, images sent to our television sets and our computers connected to the Internet. They are used in the screens of mobile telephones, barcode and QR scanners, audio and video recorders, printing, artificial vision, LED lighting and security systems such as the holograms on banknotes and credit cards. There is no doubt that light-based technologies are part of our everyday life.