World’s Tiniest Optical Gyroscope Is The Size Of A Rice Grain

gyroscope of the size of a rice grain

Gyroscopes are multi-functional devices which are used to help orient everything from vehicles to drones. They are present in almost every piece of technology that is used today. These smaller advanced gyroscope versions are called microelectromechanical sensor (MEMS) and are present in your cellphones as well. MEMs have limited sensitivity and engineers have developed a superior optical gyroscope which performs with better accuracy and with the omission of moving parts. For this, these devices depend on a phenomenon called Sagnac effect.

A French physicist Georges Sagnac worked on this optical effect which was rooted in Einstein’s theory of general relativity and works by seeing the optical gyroscope split a beam of light into two. Then it rotates to manipulate the arrival of the separate beams at its detector. This generates two twin beams which travel in the opposite directions along a circular pathway which then meet at the same light detector at different times since the rotation move has delayed the journey of one of the beams. The resulting phase shift is called the Sagnac effect and is used to calculate the orientation very precisely by optical gyroscopes.

The best high-performance optical gyroscopes are bigger than the size of a golf ball and are incompatible with most of today’s portable electronics. The previous attempts to build the smaller versions of these high-precision devices have always resulted in a reduced Sagnac effect signal and reduce the reliability and accuracy. A team of Caltech engineers which was led by Ali Hajimiri, a Bren Professor of Electrical Engineering and Medical Engineering in the Division of Engineering and Applied Science has found a way to shrink these devices while improving their accuracy at the same time. This discovery will change the use of optical gyroscopes and will make them even more popular than MEMS.

Caltech’s optical gyroscope is 500 times smaller than the best devices which are currently available in the market. This makes it smaller than a grain of rice and also enables it to detect the phase shifts which are 30 times smaller than the most precise models. To perform this, the device uses “reciprocal sensitivity enhancement.” This is a method for removing the reciprocal noise of optical gyroscopes without affecting the signals which are derived from the Sagnac effect. This way the signal-to-noise ratio in the system is improved without the requirement of a large device. The result is a tiny optical gyroscope with impressively better accuracy.


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