When a quantum dot (right) is placed next to it, the light scattering properties of a much larger gold nanoparticle (center) change. A polarized light shining on the nanoparticle generates an electric field (surrounding bands of color).
Physicists Xiaoqin "Elaine" Li, Gennady Shvets and their colleagues have been exploring new ways to manipulate light on the nanoscale. In a paper published this week in the journal Proceedings of the National Academy of Sciences, they describe work that could lead to better biological sensors and improved devices for optical communications and computing.
The researchers used an atomic force microscope, modified to act like a nanoscale robotic arm, to bring two tiny objects close together: a spherical gold nanoparticle and an even smaller quantum dot. (A quantum dot is a nanocrystal made of semiconductor materials that exhibits unusual quantum properties.) They found that the quantum dot changes the way the nanoparticle scatters light.
One possible future application might be an optical switch, analogous to a transistor in electronics except that it uses single photons to encode and process information instead of electrons. Another potential application might be a nanoscale ruler to measure very small distances in living systems in real time. Biologists could use such a sensor to study a broad range of processes including gene regulation, protein folding, protein interactions, metabolism and signaling.
One possible future application might be an optical switch, analogous to a transistor in electronics except that it uses single photons to encode and process information instead of electrons. Another potential application might be a nanoscale ruler to measure very small distances in living systems in real time. Biologists could use such a sensor to study a broad range of processes including gene regulation, protein folding, protein interactions, metabolism and signaling.
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