University of Cambridge has published an exciting article – “World’s ‘smallest magnifying glass’ makes it possible to see individual chemical bonds between atoms.”
Researchers led by the University of Cambridge have concentrated light down to smaller than a single atom using tiny particles of gold, allowing them to look at individual chemical bonds inside molecules, which is contrary to the long held belief that light, like all waves, couldn’t be focused down smaller than its wavelength. They have now paved the way to study light and matter in a new way.
The team collaborated with their European colleagues, using highly conductive gold nanoparticles to make the world’s tiniest optical cavity, small enough to only fit a single molecule within it.
The article explains:
The cavity – called a ‘pico-cavity’ by the researchers – consists of a bump in a gold nanostructure the size of a single atom, and confines light to less than a billionth of a metre. The results, reported in the journal Science, open up new ways to study the interaction of light and matter, including the possibility of making the molecules in the cavity undergo new sorts of chemical reactions, which could enable the development of entirely new types of sensors.
The team has found it challenging to build nanostructures with single atom control. “We had to cool our samples to -260°C in order to freeze the scurrying gold atoms,” said Felix Benz, lead author of the study. The researchers shone laser light on the sample to build the pico-cavities, which allowed them to watch single atom movement in real time.
Professor Javier Aizpurua from the Center for Materials Physics in San Sebastian in Spain, who led the theoretical section of this work said, “Our models suggested that individual atoms sticking out might act as tiny lightning rods, but focusing light instead of electricity.”
The lead researcher, Professor Jeremy Baumberg of the NanoPhotonics Centre at Cambridge’s Cavendish Laboratory said, “Even single gold atoms behave just like tiny metallic ball bearings in our experiments, with conducting electrons roaming around, which is very different from their quantum life where electrons are bound to their nucleus.”
The findings have the potential to open a whole new field of light-catalysed chemical reactions, allowing complex molecules to be built from smaller components. Additionally, there is the possibility of new opto-mechanical data storage devices, allowing information to be written and read by light and stored in the form of molecular vibrations.
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