Photons have been around ever since the Big Bang, which is a long time. Photons, by definition, are always on the move: 3 10 ¹⁰ cm/sec in air. Some of the important milestones in the history of the human civilization are those at which we have improved our ability to control the movement of photons. A few notable examples are the control of fire, the design of lenses, the conception of Maxwell s equations, the invention of photography, broadcast radio, and the laser.

Photonics is the study of how photons and electronics interact, how electrical current can be used to create photons as in a semiconductor laser diode, and how photons can create an electrical current, as in a solar cell. The field of photonics is in its infancy. Great discoveries remain to be made in using photonics to improve our lives.

The list of applications in photonics is long. Some of the rapidly growing areas are:

Ecology:

Solar cell energy generation

Air quality and pollution monitoring

Imaging:

Camcorders

Satellite weather pictures

Digital cameras

Night vision

Military surveillance

Information displays:

Computer terminals

Traffic signals

Operating displays in automobiles and...