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In a substantial breakthrough in imaging technology, a team of researchers has created a hyperlens using purified crystals.
In what could have major implications for research in the development of new antibiotics, for example, researchers from several US universities have collaborated to produce an incredibly powerful ‘hyperlens’.
Unlike a typical lensed microscope, hyperlensing is a method of creating lenses that can see objects much smaller than the wavelength of light. This is possible because of a fundamental advance in the quality of an optical material used in the production process.
When functioning, the hyperlens would be so powerful that it would let the observer view features the size of a small virus on the surface of a living cell in its natural environment.
In a paper published to the journal Nature Materials, the research team explained that it used a new optical crystal material called hexagonal boron nitride (hBN).
In previous hyperlens testing using hBN, researchers were able to see an object about 36 times smaller than the infrared wavelength, but this new method was able to outdo this by a factor of 10.
To do this, the team made the hBN crystals using isotopically purified boron, as natural boron contains two isotopes that differ in weight by about 10pc, a combination that significantly degrades the crystal’s optical properties in the infrared.
A lens made from the purified crystal, the team calculated, could measure objects as small as 30 nanometres. To put this into perspective, every centimetre has 10m nanometres and every human red blood cell is about 9,000 nanometres in size.
Another tenfold increase possible
By using hBN crystals made from 99pc isotopically pure boron, the researchers have measured a dramatic reduction in optical losses compared to natural crystals, increasing the polariton’s lifetime threefold, allowing them to travel triple the distance.
“We have demonstrated that the inherent efficiency limitations of hyperlenses can be overcome through isotopic engineering,” said researcher Alexander Giles.
“Controlling and manipulating light at nanoscale dimensions is notoriously difficult and inefficient. Our work provides a new path forward for the next generation of materials and devices.”
Not stopping there, the research team believes that, in theory, the resolution could be increased substantially by another factor of 10.
The team’s lead researcher, Joshua Caldwell, said: “Currently, we have been testing very small flakes of purified hBN. We think that we will see even further improvements with larger crystals.”
