Illustration of the new bowtie structure, which can be seen in the middle of the picture. The bowtie structure compresses light spatially, and the nanostructures around it store it temporally. The result is a compression of light to the smallest scale to date – the world’s smallest photon in a dielectric material. Credit: DTU
Measurement of the world’s smallest photon. a) Model of the nanocavity, where the calculated strength of the electric field is shown with the color scale. b) Magnification around the narrow strip of material in the bowtie structure in the center where photons are squeezed together. c) Measurement of the electric field that emerges when photons are sent into the cavity by shining it with a laser, i.e., a microscopic image of the world’s smallest photon.
However, nanostructures can consist of elements much smaller than the wavelength, which means that the diffraction limit is no longer a fundamental limit. Bowtie structures, in particular, can compress the light into very small volumes limited by the sizes of the bowtie and, thus, the quality of the nanofabrication.
“It required a great joint effort to achieve this breakthrough. It has only been possible because we have managed to combine world-leading research from several research groups at DTU,” says associate professor Søren Stobbe, who has led the research work.”The discovery could be decisive for developing revolutionary new technologies that may reduce the amount of energy-guzzling components in data centers, computers, telephones, etc.