Researchers at King's College London, in collaboration with European research institutes ICFO (Barcelona) and AMOLF (Amsterdam), have succeeded in mapping how light behaves in complex photonic materials inspired by nature, like iridescent butterfly wings. Scientists have broken the limit of light resolution at the nanoscale and delivered a fundamental insight into how light and matter interact, which could lead to the development of enhanced bio-sensors for healthcare and more efficient solar cells and displays.
Optical measurements of light waves at the nanoscale have always been limited by the resolution of the optical microscope, but researchers were able to break this limit using a new technique which combines electronic excitation and optical detection, to explore the inside of a photonic crystal and study the confinement of light. Working with a spatial resolution of 30 nanometers, scientists examined the structures at a resolution more than ten times smaller than the diffraction limit for light, revealing a greater understanding of how light interacts with matter to create, for example, the visible iridescence phenomena observed in nature on the wings of butterflies.
Dr Riccardo Sapienza, from the Department of Physics at King's, said: 'We were thrilled in the lab to observe the finer details of the photonic crystals that were simply inaccessible before. This is very important as it allows scientists to test optical theories to a new level of accuracy, fully characterise new optical materials and test new optical devices.'
The collaborative research has been published in the journal Nature Materials.
The team constructed an artificial two-dimensional photonic crystal by etching a hexagonal pattern of holes in a very thin silicon nitride membrane. Photonic crystals are nanostructures in which two materials with different refractive indices are arranged in a regular pattern, giving rise to exotic optical propert
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King's College London