A team of researchers, including a University of British Columbia engineer, has made a breakthrough utilizing spray-on technology that could revolutionize the way optical lenses are made and used.
Kenneth Chau, an assistant professor in the School of Engineering at UBC’s Okanagan campus, worked with principal investigator Henri Lezec and colleagues Ting Xu, Amit Agrawal, and Maxim Abashin at the National Institute of Standards and Technology (NIST) in Maryland on the development of a flat lens.
Their work – the development of a flat lens – is published in the May 23 issue of the science journal Nature, and is summarized in an online feature released by NIST.
“The idea of a flat lens goes way back to the 1960s when a Russian physicist came up with the theory,” Chau says. “The challenge is that there are no naturally-occurring materials to make that type of flat lens. Through trial and error, and years of research, we have come up with a fairly simple recipe for a spray-on material that can act as that flat lens.”
More than four years of lab work was devoted to develop a substance that can be affixed to surfaces like a glass slide. Once applied, it essentially becomes a flat lens to perform imaging with ultraviolet light – invisible to the human eye but widely used to examine biological specimens. The idea of a flat lens is novel because nearly all lenses – whether in an eye, a camera, or a microscope – are curved, which limits the aperture, or amount of light that enters.
“Curved lenses always have a limited aperture,” he explains. “With a flat lens, suddenly you can make lenses with an arbitrary aperture size – perhaps as big as a football field.”
While the spray-on, flat lens represents a significant advancement in technology, it is only an important first step, Chau says.
“This is the closest validation we have of the original flat lens theory. The recipe, now that we’ve got it working, is simple and cost-effective. Our next step is to extrapolate this technique further, explore the effect to the fullest, and advance it as far as we can take it.”
What excites Chau is that researchers now have the capability to make materials with unique properties that were once unattainable. As a demonstration of leading-edge nano-engineering, the possibilities open to myriad applications once scientists learn how to control matter at small-size scales.
“This is very complicated, very detailed work, and you have to be patient. I’ve learned a lot while working on this and it has certainly taught me to be patient and that you must always keep learning and growing.”
With research still at an early stage, Chau says it is difficult to predict future applications beyond the lab – but there is little doubt that further investigation will produce innovations. For instance, the technology could, in a few years, potentially change the way imaging devices like cameras and scanners are designed. Right now, the science appeals to those working in the field of microscopy, where lenses magnify tiny objects.
Chau is thrilled because the team’s research paper, titled All-Angle Negative Refraction and Active Flat Lensing of Ultraviolet Light, is published in Nature. The international science periodical has an expansive global audience and Chau says to be featured in such a prestigious journal is a great boost for his research.
“It’s very special to be published in Nature,” says Chau. “It gives us an opportunity to communicate with an enormous, world-wide scientific audience. The prestige factor is huge and there is an impressive list of great scientists who have published seminal work in this journal. To be part of this tradition is truly amazing and very humbling.”