A new technique involving lasers can make atomic-force microscopes 20 times more sensitive. This increase in sensitivity allows the microscope to detect incredibly small forces such as the weight of an individual virus. To wrap your head around the weight of an individual virus, it’s 100 billion times lighter than a mosquito according to Professor Ping Koy Lam, the leader of the Quantum Optics Group.
Researchers at the Quantum Optics Group of the Research School of Physics and Engineering developed this new technique. How does it work? Laser beams are used to cool a nanowire probe to minus 265 degrees Celsius.
These nanowire probes are extremely small. The silver gallium nanowire pictured below is 500 times finer than a human hair.
This new technique was designed to counter the vibration problem seen in the nanowire probes. At room temperature, the nanowire probe vibrates leading to noise in measurements. These vibrations come to a halt thanks to the laser technique.
Now, measurements can also be affected while the laser is cooling the nanowire, so researchers have to turn it off and then take measurements very quickly. We’re talking milliseconds here. As soon as the lasers are turned off, the nanowire begins to heat quickly. Researchers have to take several readings in order to get an accurate one between periods of heating and cooling.
“We now understand this cooling effect really well,” says PhD student Harry Slatyer according to Phys.org. “With clever data processing we might be able to improve the sensitivity, and even eliminate the need for a cooling laser.”
Image credit: Quantum Optics Group