Researchers at Northwestern University (NU) have developed tiny optical elements from metal nanoparticles and a polymer that may one day replace traditional refractive lenses to realize portable imaging systems and optoelectronic devices.
According to a news release posted on NU’s website on Thursday, the flat and versatile lens, a type of metalens, has a thickness 100 times smaller than the width of a human hair.
The researchers built the lenses out of an array of cylindrical silver nanoparticles and a layer of polymer patterned into blocks on top of the metal array. By simply controlling the arrangement of the polymer patterns, the nanoparticle array could direct visible light to any targeted focal points without needing to change the nanoparticle structures.
This scalable method enables different lens structures to be made in one step of erasing and writing, with no noticeable degradation in nanoscale features after multiple erase-and-write cycles. The technique can reshape any pre-formed polymer pattern into any desirable pattern using soft masks made from elastomers.
“This miniaturization and integration with detectors offers promise for high-resolution imaging in devices from small wide-angle cameras to miniature endoscopes,” said Teri W. Odom, a chemistry professor at NU’s Weinberg College of Arts and Sciences who led the research.