Photonics

Photonics is a branch of optics that involves the application of generation, detection, and manipulation of light in the form of photons through emission, transmission, modulation, signal processing, switching, amplification, and sensing. Even though photonics is a commonly used term, there is no widespread agreement on a clear definition of the term or on the difference between photonics and related fields, such as optics. Photonics is closely related to quantum optics, which studies the theory behind photonics' engineering applications. Though covering all light's technical applications over the whole spectrum, most photonic applications are in the range of visible and near-infrared light. The term photonics developed as an outgrowth of the first practical semiconductor light emitters invented in the early 1960s and optical fibers developed in the 1970s. The field is also supported by professional organizations such as the IEEE Photonics Society, which serves as a conduit for advances in photonics research, engineering, and its applications.

History The word 'Photonics' is derived from the Greek word "phos" meaning light (which has genitive case "photos" and in compound words the root "photo-" is used); it appeared in the late 1960s to describe a research field whose goal was to use light to perform functions that traditionally fell within the typical domain of electronics, such as telecommunications, and information processing.

An early instance of the word was in a December 1954 letter from John W. Campbell to Gotthard Gunther:Incidentally, I've decided to invent a new science — photonics. It bears the same relationship to Optics that electronics does to electrical engineering. Photonics, like electronics, will deal with the individual units; optics and EE deal with the group-phenomena! And note that you can do things with electronics that are impossible in electrical engineering!Photonics as a field began with the invention of the maser and laser in 1958 to 1960. Other developments followed: the laser diode in the 1970s, optical fibers for transmitting information, and the erbium-doped fiber amplifier. These inventions formed the basis for the telecommunications revolution of the late 20th century and provided the infrastructure for the Internet. Though coined earlier, the term photonics came into common use in the 1980s as fiber-optic data transmission was adopted by telecommunications network operators. At that time, the term was used widely at Bell Laboratories. Its use was confirmed when the IEEE Lasers and Electro-Optics Society established an archival journal named Photonics Technology Letters at the end of the 1980s. During the period leading up to the dot-com crash circa 2001, photonics was a field focused largely on optical telecommunications. However, photonics covers a huge range of science and technology applications, including laser manufacturing, biological and chemical sensing, medical diagnostics and therapy, display technology, and optical computing.

Relationship to other fields

Classical optics Photonics is closely related to optics. Classical optics long preceded the discovery that light is quantized, when Albert Einstein famously explained the photoelectric effect in 1905. Optics tools include the refracting lens, the reflecting mirror, and various optical components and instruments developed throughout the 15th to 19th centuries. Key tenets of classical optics, such as Huygens Principle, developed in the 17th century, Maxwell's Equations and the wave equations, developed in the 19th century, do not depend on quantum properties of light.

Modern optics Photonics is related to quantum optics, optomechanics, electro-optics, optoelectronics and quantum electronics. However, each area has slightly different connotations by scientific and government communities and in the marketplace. Quantum optics often connotes fundamental research, whereas photonics is used to connote applied research and development. The term photonics more specifically connotes:

The particle properties of light, The potential of creating signal processing device technologies using photons, The practical application of optics, and An analogy to electronics. The term optoelectronics connotes devices or circuits that comprise both electrical and optical functions, i.e., a thin-film semiconductor device. The term electro-optics came into earlier use and specifically encompasses nonlinear electrical-optical interactions applied, e.g., as bulk crystal modulators such as the Pockels cell, but also includes advanced imaging sensors. An important aspect in the modern definition of Photonics is that there is not necessarily a widespread agreement in the perception of the field boundaries. Following a source on optics.org, the response of a query from the publisher of Journal of Optics: A Pure and Applied Physics to the editorial board regarding streamlining the name of the journal reported significant differences in the way the terms "optics" and "photonics" describe the subject area, with some description proposing that "photonics embraces optics". In practice, as the field evolves, evidence that "modern optics" and Photonics are often used interchangeably is very diffused and absorbed in the scientific jargon.

Emerging fields Photonics also relates to the emerging science of quantum information and quantum optics. Other emerging fields include:

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