Follow the light
Mapping the orientation of light fields on a microscopic scale is shown to be possible for the first time in the first issue of Nature Photonics. Light is made up of fields with a direction as well as an intensity. Most optical probes measure only the strength of the field. But Kwang Geol Lee and colleagues have built a microscope that allows the direction of the electric field to be captured down to a nanometre scale.Their device contains a nano-sized gold particle attached to the tip of a glass fibre. By scanning the tip along the surface of an object and capturing light that is scattered off the nanoparticle, they can create an image of the sample and uncover features smaller than the wavelength of the light. Lee and co-workers insert a polarizer just in front of the imaging camera that allows them to identify the components of the electric field.This new way of ‘seeing’ light tells us how light behaves near very tiny objects. It could help in the design of miniature optical components, or lead to new biosensors, where light interacts with biological molecules in different ways depending on the orientation of the electric field.
Author contact:DaiSik Kim (Seoul National University, Korea)Tel: +82 2880 8174; E-mail: dsk@phya.snu.ac.kr