A new development on the technology for optical gyroscopes could allow the devices to have increased sensitivity while decreasing to a size of only 10 μm.
A study by researchers from the City University of New York and Yale University shows that far-field emission patterns of light have strong interactions with microdisk optical cavities that are rotating, which presents an alternative to the optical gyroscopes currently being used for applications such as rocket and satellite guidance.
Gyroscopes that utilize far-field emission patterns can be made very small, measuring only a fraction of the width of a strand of human hair. The very small size is a significant development to the currently used optical gyroscopes that have sizes ranging from that of a basketball to a baseball. The new gyroscopes can be included in circuit boards, which would lead to a massive reduction in the cost of equipment for space missions.
The optical gyroscopes can be started by pumping light waves into the device's optical cavity. The light waves simultaneously travel in both the clockwise and counterclockwise direction, with the researchers being able to control where the light waves exit the gyroscope through the design of the gyroscope's optical cavity.
While optical cavities are normally used to contain light for as long a time as possible, the researchers used the cavities to create a far-field emission pattern by allowing light to exit. Two detectors are included in the cavity for constant monitoring of the pattern, determining the rotation speed of the gyroscope.
Previous optical gyroscopes utilized the Sagnac effect, which is the creation of interference patterns as light waves are split and recombined upon escaping a spinning body. However, such gyroscopes lose sensitivity as the optical cavity wherein light waves pass become smaller, which hindered the development of tiny gyroscopes.
"There have been several attempts to get around this limitation, but they could not get around the real problem, the Sagnac effect itself," said CUNY Graduate Center and Staten Island College professor Li Ge.
The researchers said that additional studies are required to analyze the possibility that there are several light modes existing simultaneously within the optical cavity for the new gyroscopes. The far-field emission patterns could change in different ways, causing reduced rotation sensitivity for the devices. The scientists are currently working on ways to manage the undesirable effect.
The research, entitled Rotation-induced evolution of far-field emission patterns of deformed microdisk cavities, was published in the Optica journal.
