This article defines the word photonics and explains the origin of the word.

Before getting into a definition of photonics, we first have to define what a photon is.

Good luck with that.

Every year at the SPIE Photonics West conference, there is a late-night panel called “What is a Photon?” at which more-or-less sober physicists still argue about the exact nature of photons. Trying to nail down a technical definition of a photon quickly spirals into abstract particle physics, and that’s not useful from a business perspective. A practical definition of a photon is this:

Photons are sub-atomic particles that are the fundamental building blocks of light in the same way that electrons are the fundamental building blocks of negative electric charge.

I will leave it at that.

The origin of the word photonics can be traced to a 1974 conference in France called, appropriately, “Photonics.” At the meeting, an international cross-section of specialists set out to define a growing area of research that, up to that point, was ambiguously named (and hyphenated) as either electro-optics or opto-electronics. The conference was meant to settle the terminology and be “the birth certificate for a new technological field which will certainly be developed in the near future.” The conference proceedings, which were edited by M. Balkanski and P. Lallemand, are not available online, although I have ordered a print copy. Fortunately, in the meantime and thanks to the resources at the University of Rochester’s Physics, Optics and Astronomy library, I tracked down a print copy of an English translation of a Russian review of the French conference. (You should be impressed by that.) The summary article was written by P. Feofilov in Optical Spectroscopy—a Russian journal translated into English by the Optical Society of America.

A photocopy image from P. Feoliv's 1976 summary of the 1974 Photonics conference, in which he provides a definition of the word photonics. The summary appeared in in the journal Optical Spectroscopy.
“Photonics. Edited by M. Balkanski and P. Lallemand. Gauthier-Villars, Paris, 1975, 412 pp.”, reviewed by P. Feofilov, Opt. Spektrosk. 40, 204–205 (January 1976).

I have attached a photocopy of a portion of Feofilov’s article. In it, he gives what might arguably be called the “definitive definition” of photonics.

The editors use photonics (by analogy with electronics) to denote the phenomena and devices in which information is carried by photons (the role played by electrons in electronics)… The necessity for outlining a new field arises because the development of semiconductor lasers, fiber optics, and highly sensitive rapid radiation detectors has opened the way for different and very promising methods of constructing new optical devices, primarily for utilization in optical communications and for recording, storage and processing of optical information.

Merging all that information, we can construct the following practical definition of photonics:

Photonics occupies a region of intersection between optical and electrical research and development. Photonics is devoted to using photons to communicate, record, store, and process optical information in analogy to the way that electronics use electrons to communicate, record, store, and process electrical information.

I would be remiss if I failed to note the enormous contribution of the scientist Herwig Kogelnik in popularizing the word photonics. Kogelnik, a pioneering scientist from Bell Labs, was one of the preeminent attendees at the Photonics conference. In 1982, at the Conference on Lasers and Electro-Optics (CLEO), Kogelnik presented an invited paper titled “Optics and photonics: electrooptics for the Eighties.” That talk seems to have been hugely influential in establishing the word photonics as the official name of the new field.

3 thoughts on “Why Do We Call Photonics “Photonics”?

  1. All the fifty years of conscious brooding have brought me no closer to the answer to the question: “What are light quanta?” Of course today every rascal thinks he knows the answer, but he is deluding himself.


    If you ask a physicist what is his idea of yellow light, he will tell you that it is transversal electromagnetic waves of wavelength in the neighborhood of 590 millimicrons. If you ask him: But where does yellow come in? he will say: In my picture not at all, but these kinds of vibrations, when they hit the retina of a healthy eye, give the person whose eye it is the sensation of yellow.


    Thus the colors with their various qualities and intensities fulfill the axioms of vector geometry if addition is interpreted as mixing; consequently, projective geometry applies to the color qualities.


    Surprisingly, the Langlands dual group also appears in quantum physics in what looks like an entirely different context; namely, the electromagnetic duality. Looking at the Maxwell equations describing classical electromagnetism, one quickly notices that they are invariant under the exchange of the electric and magnetic fields. It is natural to ask whether this duality exists at the quantum level.


    • Thank you for the response, Brian. I particularly appreciate the quotes from Albert Einstein and Erwin Schrödinger. I may use them in the upcoming blogs.

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