The existence of ultrasound has long been known. For decades, the technology has helped submarines navigate the space, and doctors — to examine patients without surgery. Modern ultrasound machines have power limitations, but researchers at the University of Queensland have figured out how to increase their power by almost a hundred times. They claim that the new device is able to catch the sound of air molecules movement and even vibration of individual cells.
Usually, ultrasonic devices consist of a receiver and an emitter made of piezoelectric crystals. When they are exposed to electric current, they vibrate and produce high — frequency sounds above 20,000 Hertz-as is known, they are not perceived by the human ear. The emitted sound waves pass through the air, water and soft tissues, and bounce off hard surfaces at different speeds. When they return to the crystals, the reverse process occurs — the vibrations create an electric current that allows the computer to recognize the shape of the object from which the waves are pushed. Thus, for example, you can see the embryo in the womb.
To increase the strength of the device, the researchers used a different design: the receiver consists of a tiny quartz disk 148 microns wide and 1.8 microns thick. Behind it is a laser that instantly reads the smallest distortion on the disk caused by the reflected sound waves. Increased sensitivity allows you to get more detailed information and even hear how the bacteria move.
The technology is based on a new capability that we developed using laser light to measure mechanical motion at the nanoscale, at the level of attometers (a thousandth of the width of an atomic nucleus). This possibility has been developed for the implementation of new quantum technologies — here we use it instead of ultrasonic sensing. The ultrasonic wave causes mechanical vibrations of the micro-scale structure on the silicon chip, which we then read with laser light.
Warwick Bowen, author of the study
The technology can be used to listen to individual cells and bacteria. Thanks to it, researchers can find out not only whether the cells are alive, but they are normal or cancer. They will also be able to learn more about the processes occurring inside and monitor the movement of bacteria. The use of technology in engineering can improve the accuracy of underwater vehicles and improve medical equipment.