The word "Sagnac rays" refers to the phenomenon of light circulating around a closed path in a rotating interferometer. It is pronounced as /sæɡnæk reɪz/ with the stress on the first syllable. The spelling of "Sagnac" comes from the French physicist Georges Sagnac who first reported this effect in 1913. The word "rays" is spelled as it sounds in English, with the phonetic transcription /reɪz/. "Sagnac rays" have important applications in navigation systems and inertial guidance.
Sagnac rays refer to the phenomenon that occurs when a beam of light travels along a closed loop or a closed path in a rotating frame of reference. Named after French physicist Georges Sagnac, the Sagnac effect is a result of the rotation of the apparatus through which the light is passing.
In the Sagnac effect, when a beam of light is split into two separate beams and made to travel in opposite directions along a closed loop, the two beams will experience a relative phase shift due to the rotation of the apparatus. This phase shift is caused by the difference in the distances traveled by the light beams. As a result, interference occurs when the two beams are recombined.
The interference pattern created by the two beams can be used to measure the rotation rate of the apparatus. By comparing the measured phase shift to a reference value, the rotation rate of the system can be determined. This effect is extensively utilized in devices such as ring laser gyroscopes, which are employed for precision measurement of rotation rates in various applications, including navigation systems, geodesy, and inertial guidance.
In summary, Sagnac rays are the beams of light that travel along a closed loop in a rotating frame of reference, exhibiting a phase shift caused by the rotation. The measurement of this phase shift enables the determination of the rotation rate of the system.
• Secondary rays.
• Secondary rays produced when x-rays or gamma rays impinge upon the surface of any body; they resemble or are identical with the beta rays.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.