What Is an Optical Cavity?

Malcolm Tatum
Malcolm Tatum

Also known as an optical resonator, an optical cavity is an arrangement designed to control the feedback generated from light waves. Typically, this type of arrangement will involve the use of mirrors or some other means of reflecting those waves to create a desired effect. The optical cavity is an essential part of various types of laser based equipment, making it possible to control the direction and intensity of the light waves so the laser can be used for specific purposes. Technology of this type has made it possible to develop laser equipment for a wide range of uses, including security systems and even life-saving procedures for use in medical facilities.

A laser barcode scanner uses an optical cavity to intensify its light.
A laser barcode scanner uses an optical cavity to intensify its light.

A simple configuration of an optical cavity will involve a minimum of two mirrors that are carefully positioned to allow the light waves to be reflected a number of times between the mirror surfaces. The end result is the ability to control the resonance created by the light waves and even control the direction and intensity of those waves. Depending on the type of equipment involved and the design of the laser itself, just about any number of mirrors functioning as prisms may be involved.

One of the benefits of the optical cavity is to control the resonance generated with the light waves, allowing the operator of the equipment to adjust frequency using the basic controls on the device. This process can be used to create lasers suitable for everything from soldering components on PC boards to aiding in surgical procedures and other healthcare-related tasks. The configuration of the optical cavity also serves as a safety measure, since the placement and number of reflective devices or mirrors will effectively set a limit on the intensity of the resonance produced from the process.

Factors that will influence the function of an optical cavity include the size and shape of the mirrors used to create the effect. It is unusual for flat mirrors to be used, owing to the difficulty of adjusting the position of the mirrors to create the desired effect. More often, curved mirrors are preferred for use in the cavity, and can be adjusted with relative ease so the proper amount of reflection is achieved. In addition the length of the mirrors involved will also make a difference to the resonance and frequency that is created. Even something as simple as the distance that exists between the mirrors will impact how efficiently the optical cavity ultimately functions.

Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including wiseGEEK, and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

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