Photon seesaw mechanism demonstrates transport of light

According to the university, the discovery could have implications for creating faster and more efficient optical devices for computation and communication.

The research paper by University of Minnesota electrical and computer engineering assistant professor Mo Li and his graduate student Huan Li has been published online and will appear in the October issue of Nature Nanotechnology.

The researchers’ nanoscale device can capture, measure and transport photons. The device is 0.7 micrometres by 50 micrometre (about .00007 by .005 centimetres) and has been likened to a ‘photon seesaw’. On each side of the ‘seesaw benches,’ researchers etched photonic crystal cavities that capture photons streamed from a nearby source.

Even though the particles of light have no mass, the captured photons were able to move the so-called seesaw because they generated optical force.

Researchers compared the optical forces generated by the photons captured in the cavities on the two sides of the seesaw by observing how the seesaw moved up and down. In this way, the researchers weighed the photons. Their device is claimed to be sensitive enough to measure the force generated by a single photon, which corresponds to about one-third of a thousand-trillionth of a pound or one-seventh of a thousand-trillionth of a kilogram.