Breaking the diffraction limit

The nanophotonics panel: Jennifer Dionne (left), Satoshi Kawata (middle) and Adarsh Sandhu.

By Hamish Johnston

At first glance, visible light and nanotechnology seem incompatible because of the diffraction limit, which dictates that features smaller than about half the wavelength of light cannot be resolved optically. For visible light, the diffraction limit is about 300 nm and this means that there is no point in trying to make conventional optical components that are any smaller.

But that pessimistic outlook has changed over the past decade or so thanks to the development of nanophotonics, which makes use of near-field (or evanescent) light and plasmons to manipulate light on length scales much smaller than the diffraction limit. Today, nanophotonics is being used across a range of disciplines, including biological imaging, telecommunications, solar energy and semiconductor processing.

In the latest in the series of Nanotechnology Discussions, Anna Demming of nanotechweb.org speaks to three experts in the field of nanophotonics about the basics of why size matters when designing new technologies, as well as a range of exciting new applications of nanophotonics.

Demming’s panel of experts are Jennifer Dionne of Stanford University in the US, Satoshi Kawata of Osaka University in Japan and Adarsh Sandhu of Japan’s Tokyo Institute of Technology and Toyohashi University of Technology.

You can listen to the discussions here: “Electromagnetism at the nanoscale”.