What is Photonics?

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Photonics is the science of generating, controlling and detecting light. The field is at the cross-roads of several disciplines including physics, electronics, mathematics and chemistry. Photonics in simple terms can be seen as analogous to electronics. The flow of electricity in a wire consists of the combined movement of fundamental particles of charge, called electrons. The devices and systems used to generate and manipulate electrical signals are grouped under the banner of electronics. Experimental and theoretical work carried out by many leading physicists, includng Albert Einstein, at the beginning of the 20th century, changed the way we understand the nature of light. It was shown that light consists of a fundamental particle, called a photon, which can be seen as a packet of light. Therefore in analogy to electronics, the flow of these photons in a beam of light or through a material gave rise to the term photonics.

The widespread prevalence of electronics in modern life is clear for all to see in the products we take for granted such as the computer you’re now using. In comparison the impact of photonics is perhaps less visible and not just because many of the advances involve wavelengths (or colours) of light that are invisible to the human eye. The colours that we see only form a small part of the broad spectrum of light that exists. Ultraviolet (UV) light, which has wavelengths shorter than the violet which our eyes can see, is probably most associated with sunlight and its effect on our skin. Despite being invisible to us, UV light has a great many useful applications in diverse fields such as curing of adhesives, security tagging and biological imaging. Infra-red (IR) light has wavelengths longer than the red we can see with our eyes and we commonly associate it with the generation of heat given that we all radiate IR light from our bodies. As a result one of the most widely know applications of IR is thermal imaging but IR technology is used in fields such as spectroscopy, telecommunications, electronics and astronomy.

Photonics is a key enabling technology of the 21st century. At the later part of the 20th century the continued development of the semiconductor laser enabled long haul fibre-optic communication to become a reality. As well as revolutionising telecommunications these advances also enabled the development of the internet. While the internet could not have evolved without photonics, the use of light has become a seamless part of our everyday lives beyond communications. There are obvious photonic applications, such as checkout scanners, remote controls, car lights and DVD players, with which we interact with on a daily basis. Moreover many of the products we use, from pharmaceutical drugs to mobile phones, are manufactured, inspected and tracked using photonic technologies. Through our own research, as well as academic and commercial partnerships, CAPPA explores a wide range of existing and emerging technologies and applications across this exciting field.