RingLaserGyroskop

A ringlasergyroskop, or ring laser gyroscope (RLG), is a type of optical gyroscope that measures angular velocity by exploiting the Sagnac effect in a closed-loop laser cavity. When the device rotates, light traveling in opposite directions around the loop accumulates a different phase, producing a measurable frequency difference between the counterpropagating beams.

In a typical ring laser gyroscope, a single-frequency laser produces two beams that propagate around a planar or closed ring formed by mirrors. The beams are frequency-shifted relative to each other by the rotation, and they are combined to generate a beat frequency at a photodetector. The observed beat frequency f is proportional to the rotation rate Ω, and for a ring with enclosed area A and optical path length P, f ≈ (4 A Ω)/(λ P), where λ is the light wavelength. This enables direct measurement of angular velocity without moving mechanical parts.

RLGs are valued for high sensitivity, wide dynamic range, and robustness, making them suitable for inertial navigation in aircraft, submarines, and spacecraft, as well as for geophysical experiments and precision measurements of Earth's rotation. Practical performance depends on factors such as mirror quality, cavity stability, laser noise, and environmental isolation. A common limitation is the lock-in or dead band at very low rotation rates caused by backscattering between counterpropagating beams; methods such as dithering or biasing are used to mitigate this effect.

Variations include square, triangular, or circular ring geometries, and ongoing research explores miniaturized or integrated implementations alongside traditional macroscopic configurations.