A new way has been found by Laser physicists for making atomic-force microscope probes 20 times more capable and sensitive of detecting forces that are as small as weight of individual virus.
This technique was developed by researchers in Quantum Optics Group of Research School of Physics and Engineering and it hinges on the use of laser beams for cooling a nanowire probe to -265 degrees Celcius.
The leader of Quantum Optics Group, Professor Ping Koy Lam, said that the level of sensitivity that was achieved after cooling is accurate for sensing the large virus’ weight which is 100 billion times lighter as compared to a mosquito.
This development can be used for bringing about an improvement in the resolution of atomic-force microscopes, which are considered to be state-of-the-art tool to measure tiny forces as well as nanoscopic structures between the molecules.
Extraordinarily sensitivity measurements are achieved by Atomic force microscopes of microscopic features. A wire probe is scanned over the surface.
These probes are 500 times finer as compared to human hair and are prone to vibration. At the room temperature, probes are seen vibrating, owing to the warmth. Due to this, the measurements can be made noisy. However, if lasers are shone at the probe, this motion can be stopped.
The ANU team used a force sensor that was a 200 nm-wide silver gallium nanowire having a gold coating. This nanowire is 500 times finer as compared to huma hair. Due to the laser, the probe is made warp and moves due to heat. However, this warping effect is controlled and the effect can be used for countering the probe’s thermal vibration.
However, this probe can’t be used when the laser is on, as the sensitive probe is overwhelmed by laser effect. Thus, turning of the laser is important before heating of the probe happens.