Researchers are on their way to creating the world's smallest gyroscope using light, and the findings could break ground in the navigation industry.
A pair of light waves moving in different directions could be the key to creating a gyroscope a fraction of the width of a human hair, the Optical Society reported.
"We have found a new detection scheme that may lead to the world's smallest gyroscope," said Li Ge, a physicist at the Graduate Center and Staten Island College, City University of New York. "Though these so-called optical gyroscopes are not new, our approach is remarkable both in its super-small size and potential sensitivity."
Traditional mechanical gyroscopes use Newton's laws of motion to maintain stability, but this principle does not apply to light, so researchers must use optical signals to measure its motion. One of these signals is the property of light known of as the Sagnac effect, which creates a measurable interference pattern when light waves split and recombine. Researchers have taken two approaches to creating gyroscopes, both based on the Sagnac effect.
The first approach uses an optical cavity, and the second uses an optical fiber to guide light. The former approach is believed to be most promising for creating a gyroscope that is super small, but the problem is the sensitivity of the gyroscope degrades as the cavity gets smaller. To overcome this, the researchers used a principle of far-field emission, which allowed them to measure patterns of light as it left the cavity.
"That was our key innovation - finding a new signal with a much improved sensitivity to rotation," Ge said. "Optical gyroscopes optimized to produce and detect this new signal, we found, could be about 10 microns across - smaller than the cross section of a human hair."
To start this new type of gyroscope, light waves are pumped into the optical cavity, producing light waves that travel in opposite directions. The design of the optical cavity ensures researchers can control were the light waves exit, as well as measure the far-field emission patterns they create.
The findings were published in a recent edition of the journal Optica.
