Photonics is a broad field of study that involves the research and application of light in all of its many forms. The field is not only interested in the visible light spectrum; ultraviolet light and infrared light are very important as well. The field of photonics was originally aimed at applying light to tasks that could previously only be solved through electronics, such as telecommunications. The modern field seeks to continue this endeavor and to expand upon it by searching for any and all applications for light. Photonics draws from and contributes to several other fields, such as quantum electronics and modern optics.
There are many aspects of light and its behavior that are important to those studying photonics for scientific or industrial purposes. Light transmission, for example, is important because of the need for efficient and reliable data movement to and from distant locations. Fiber optic cables are often used for this purpose. Light emission and amplification are also important for the production and manipulation of effective signals.
Light sensing is particularly important in photonics, as the light involved in experiments and tests often needs to be quantified and may not even be visible. Some devices for light detection are chemical in nature; for example, light of a specific frequency or intensity may cause a specific chemical effect. Other detectors act like thermometers and respond to the heat supplied by incoming light.
The field of photonics is used in many different industries, ranging from consumer electronics to robotics. Bar code scanners and DVD readers are both light-based technologies, for example. In medicine, light in the form of lasers is used for eyesight correction and tattoo removal as well. Military applications include the detection of infrared light to expose heat sources in the dark. Some applications of photonics are used entirely for entertainment; these include laser shows and holographic art.
The wide range of commercial, industrial, and military applications in the field of photonics ensures that it is generally a well-funded and thriving area of scientific research. There are many facets to the study and application of light, so there are many different aspects of light behavior and use that can be studied at any given time. One common field of study is in modulation, the way in which information can be coded into light. The simplest method of modulation is switching a single light source on and off according to a specified code, such as Morse code. Other methods of modulation, such as orthogonal frequency-division multiplexing, seek to use different qualities of different light sources, such as frequency, to send more complex and more efficient signals.