A crucial sensing technology based on optical gyroscopes has been scaled down to about the size of a grain of sand by a team of Israeli researchers.
Despite the fact that such technology is hardly new, the miniscule size of the object still seems incredible to the layperson. But not to Prof. Koby Scheuer of Tel Aviv University’s School of Physical Engineering. "This is actually conventional technology – similar to that used by Intel, for example, to realize micro processors. It is called Photo and E-beam lithography and it is used for writing very small structures on metals, semiconductors, and other materials," he explains.
"Gyroscopes are essential elements in determining the position, orientation and velocity of any object" says Scheuer, who is working with the support of Israel’s Ministry of Defense). When available, the nano-gyroscopes will improve technologies that we use every day, such as "cell phones, mobile electronics, GPS receivers and micro surgery," he adds.
It fits on the head of a pin
Also known as rotation sensors, optical gyroscopes are widely used as navigational tools in vehicles ranging from ships to airplanes. They measure the rotation rates of a vehicle on three axes to evaluate its exact position and orientation.
Scheuer’s device will be superior to those in existence to date, and provide greater accuracy he says, because "it is based on a different physical effect (compared to conventional gyros) which enables enhanced resolution and sensitivity.
The nano-sized optical gyroscopes developed by the TAU scientists can fit on the head of a pin, or on an average-sized computer chip, without compromising the device’s sensitivity. These gyroscopes will have the ability to pick up smaller rotation rates, delivering higher accuracy while maintaining smaller dimensions, says Scheuer.
"Conventional gyroscopes look like a box, and weigh two or three pounds," he explains, "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.
"A small gyro would be useful to help in realizing very small navigation systems – for cell phones for example, or, and this may still be a bit ‘science fiction’, capsules that move inside the blood stream to deliver a drug to a precise place," he says.
Significantly-improved tracking function
When you rotate an iPhone, for example, the screen adjusts itself accordingly. A nano-gyroscope would improve the performance of this feature and be sensitive to smaller changes in position, says the professor.
And that’s not all. Nano-gyroscopes integrated into common cell phones could provide a tracking function beyond the capabilities of existing GPS systems. "If you find yourself in a place without reception, you would be able to track your exact position without the GPS signal," he relates.
Benefits to medical science are also in the offing. Scheuer may refer to them as "science fiction", but small capsules that contain cameras already pass through the body during some diagnostic procedures. However, to know exactly where the capsule is within a patient, doctors must track its signal from the outside. With the addition of a nano-gyroscope, the capsule would have a built-in navigation system, which would provide the ability to move it to more specific and precise locations within the body.
The research was recently described in the journal Optics Express.
At the core of the new device are extremely small semi-conductor 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-micrometers in diameter, as compared to the conventional gyroscope, which measures about six to eight inches, says Scheuer. The device itself, when finished, will look like a small computer chip.
Measuring a millimeter by a millimeter (0.04 inches by 0.04 inches), about the size of a grain of sand, it can be built onto a larger chip that also contains other necessary electronics.
Gyroscope ‘technology’ since 1743
Searson’s Speculum, a device that could be aligned with the horizon for use at sea, was tested for the first time in 1743. It ultimately led to the ‘discovery’ of the gyroscope in 1817, although the name wasn’t coined until 1852.
The first working gyrocompass for ships was developed by H. Anschütz-Kaempfe in 1908, which is also when the first apparatus for steadying a ship was installed in England. One year later, the first automatic pilot for aircraft was built, using gyroscopes.
Since its inception, the space, medical and consumer electronics industries have relied on gyroscopes for accuracy and safety. Scheuer began to focus on gyroscopes "about five years ago, when I realized that the type of research I was working on could be useful for rotation sensing."
He and his team of researchers are currently working on lab demonstrators of their new device, which he predicts will be ready for testing in a few years’ time. However, he says that we won’t be benefiting from it for "… several years, at least five to eight."