Physicists at the Research School of Physics and Engineering of the Australian National University in Canberra, Australia, have created a new way to make an atomic-force microscope 20 times stronger.
The microscope is so sensitive that it can detect things as small as an individual virus' weight by cooling it over 400 degrees below zero Fahrenheit, according to a new study in Nature Communications.
Atomic-force microscopes are among the most popular instruments for studying nanoscale structures and measuring the forces in action between molecules.
Scientists improved this tool with a new technique that utilizes laser beams in order to reduce the temperature of the microscope's nanowire probe to cold temperatures.
The microscope functions by moving a probe over the specific surface it wants to measure.
The probe is 500 times thinner than an average human hair unfortunately, and can be affected by vibrations that prevents scientists from taking accurate measurements.
"At room temperature the probe vibrates, just because it is warm, and this can make your measurements noisy." Researchers discovered, however, that a laser can actually reduce the temperature of the probe thus overcoming said vibrations." said Ben Buchler, co-author of the study, according to Phys.org. "The level of sensitivity achieved after cooling is accurate enough for us to sense the weight of a large virus that is 100 billion times lighter than a mosquito."
The research team discovered that they could not use the microscope's probe with the laser turned on due to the energy from the laser overwhelmed the probe's measurements.
They solved the problem by turning off the laser and taking their measurements in the few milliseconds before the nano-probe warms to room temperature.
By taking those measurements more than once during multiple heating and cooling cycles, they were able to find the "accurate final value."
"If you imagine that during one time period you just observe the motion of the wires, that gives you information that in the next time period you use to (predict) something," Researcher Ping Koy Lam said, according to Phys.org. "By observing the period before, you can predict if there was anything present to cause the wire to behave in a certain way, for example." He concluded that the "effect can then be subtracted from subsequent measurements to provide an increasingly accurate result."