Physicists at Delft University of Technology have developed a new technology on a microchip that combines two Nobel Prize-winning techniques for the first time. This breakthrough could lead to high-precision position measurements in opaque materials, such as underwater or for medical imaging, by using sound vibrations instead of light.
The microchip consists mainly of a thin ceramic sheet shaped like a trampoline with holes to enhance its interaction with lasers. It has a thickness about 1000 times smaller than a hair. When a simple laser beam is pointed at it, the trampoline’s surface vibrates intensely. The reflected laser light from the vibrating surface shows a pattern of vibrations in the shape of a comb. This comb-like signature functions as a ruler for precision measurements of distance.
The technology is easy to produce and doesn’t require any precision hardware. “It only requires inserting a laser, and nothing else. This makes it a very simple and low-power technology, that is much easier to miniaturize on a microchip,” says Richard Norte, one of the researchers. The new technology is based on two unrelated Nobel Prize-winning techniques called optical trapping and frequency combs. The combination of both concepts led to the creation of an easy-to-use microchip technology based on sound waves.
The forces exerted by the laser create overtone vibrations in the trampoline membranes. Optical trapping, a Nobel Prize-winning technique from 2018, allows researchers to manipulate even the smallest particles with extreme precision. “You can compare the overtones in the trampoline to particular notes of a violin,” Norte explains. “If you touch the string only very lightly and play it with a bow, you can create overtones; a series of notes at higher frequencies. In our case, the laser acts as both the soft touch and the bow to induce overtone vibrations in the trampoline membrane.”
The technology has the potential to measure positions in opaque materials using sound waves. It could be used for precision measurements underwater to monitor the Earth’s climate, for medical imaging, and for applications in quantum technologies. The technology’s ease of use could have significant implications for how we measure the world around us.