Tracking Device Fits on the Head of a Pin

Optical gyroscopes, also known as rotation sensors, are widely used as navigational tools in vehicles from ships to airplanes, measuring the rotation rates of a vehicle on three axes to evaluate its exact position and orientation. Koby Scheuer of Tel Aviv University’s School of Physical Engineering is now scaling down this crucial sensing technology for use in smart phones, medical equipment and other, more futuristic, technologies.

Researchers at Tel Aviv University’s School of Physical Engineering have developed a tiny optical gyroscope that may improve the performance of medical devices, cell phones and more.

Working in collaboration with Israel’s Department of Defense, Scheuer and his colleagues developed nanoscale optical gyroscopes that can fit on the head of a pin – and, more usefully, on an average-sized computer chip — without compromising the device’s sensitivity. These gyroscopes can sense slighter rotation rates, delivering higher accuracy while maintaining smaller dimensions, he says. The research was recently described in the journal Optics Express.

“Conventional gyroscopes look like a box, and weigh two or three pounds,” Scheuer said. “This is fine for an airplane, but if you’re trying to fit a gyroscope onto a smaller piece of technology, such as a cell phone, the accuracy will be severely limited.”

At the core of the new device are extremely small semiconductor lasers. As the devices start to rotate, the properties of the light produced by the lasers changes, including the light’s intensity and wavelength. Rotation rates can be determined by measuring these differences.

These lasers are a few tens of microns in diameter, as compared to the conventional gyroscope, which measures about 6 to 8 in., according to Scheuer. The device itself, when finished, will look like a small computer chip. Measuring 1 mm × 1 mm – about the size of a grain of sand – the device can be built onto a larger chip that also contains other necessary electronics.

Scheuer and his team of researchers are currently working on lab demonstrators of the device, which he predicts will be ready for testing in a few years’ time.

When available, the nanogyroscopes will improve technologies that we use every day. When you rotate an iPhone, for example, the screen adjusts itself accordingly. A nanogyroscope would improve the performance of this feature and be sensitive to smaller changes in position, Scheuer said. Additionally, nanogyroscopes integrated into common cell phones could provide a tracking function beyond the capabilities of existing global positioning systems (GPSs). “If you find yourself in a place without reception, you would be able to track your exact position without the GPS signal,” he said.

There are benefits to medical science as well. Using current technology, small capsules that contain cameras pass through the body during some diagnostic procedures. To know where the capsule is within a patient, however, a doctor must track the camera’s signal from the outside. With the addition of a nanogyroscope, Scheuer said, the capsule would have a built-in navigation system, which would provide the ability to move the capsule to more specific and precise locations within the body.

For more information, visit: www.tau.ac.il