A new ultrathin flat lens for the perfect image

Merely 60 nanometers thick, the flat lens created by applied physicists at the Harvard School of Engineering and Applied Sciences (SEAS) is essentially two-dimensional, yet its focusing power approaches the ultimate physical limit set by the laws of diffraction.

"Our flat lens opens up a new type of technology. We're presenting a new way of making lenses. It's extremely exciting," says principal investigator Federico Capasso, professor of applied physics at the Harvard School of Engineering and Applied Sciences (SEAS).

Capasso and collaborators created the flat lens, a mere 60 nanometres thick, (nanometre is a billionth part of a metre) by plating a very thin wafer of silicon with a nanometre-thin layer of gold, the journal Nano Letters reports.

The flat lens eliminates optical aberrations such as the 'fish-eye' effect that results from conventional wide-angle lenses, according to a SEAS statement.

The resulting image or signal is completely accurate and does not require any complex corrective techniques, the researchers said.

"In the future we can potentially replace all the bulk components in the majority of optical systems with just flat surfaces," said lead author Francesco Aieta, in a statement.