Recently, a team from DELFT University of Technology (DELFT) in the Netherlands has developed an on-chip technology to measure distances in materials, such as underwater or medical imaging, with high precision. The technology, which relies on sound vibrations and is suitable for high-precision position measurements of opaque materials, could lead to new techniques for monitoring the Earth's climate and human health.
The researchers used a combination of optical capture and frequency combing techniques to build their microchip, which consists mainly of a thin ceramic sheet shaped like a trampoline. The sheet, which has special holes to enhance its interaction with lasers, is about 1,000 times thinner than the diameter of a human hair.
The surface of the thin ceramic sheet vibrates violently when it comes into contact with a laser beam. By measuring the laser light bouncing off the vibrating surface, the researchers found and observed a comb shaped vibration pattern that they had never seen before. The team concluded that the comb - like feature could be used as a "ruler" to accurately measure distances.
The main challenge of frequency comb operation is the strict requirements for driving frequency and power. And the researchers demonstrated a mechanism to create a frequency comb consisting of mechanical overtones of a single characteristic frequency -- achieved by integrating a suspended dielectric film with an anti-propagation optical trap as a whole.
The technology is unique in that it does not require sophisticated hardware and is easy to produce. This method uses only milliwatt CW laser beams. "We don't need complex feedback loops or tweaking certain parameters to make our technology work," said Richard Norte, assistant professor at DELFT University of Technology (DELFT). This makes it a very simple and low-power technology that is easier to miniaturize on a microchip. Given the small size of these microchip sensors, we may be able to put them anywhere in the future."
Optical frequency combs, which won the Nobel Prize in 2005, are used in laboratories around the world for very accurate time measurements and distance measurements. In this study, the scientists created an acoustic frequency comb that is made of sound vibrations in the membrane instead of light. The easy-to-use microchip technology based on sound waves will be used in a wider range of scenarios in the future.
Source: OFweek
