Twente discovers ‘new’ shapes of photons and novel applications

09 Jul 2024

Including smarter LED lighting, photonic bits of info controlled by quantum circuits, and nano-sensors.

Researchers from the University of Twente, in the Netherlands, say that they have gained “important insights” into photons, which “behave in an amazingly greater variety than electrons surrounding atoms, while also being much easier to control.”

The new insights, described in a paper in Physical Review B promise a range of applications, from smart LED lighting, new photonic bits of information controlled with quantum circuits, to sensitive nano-sensors.

Photonics researchers describe the region of space where a photon is most likely found using “orbitals” – in a similar way that electrons are said to orbit atomic nucleii.

The Twente team studied these photonic orbitals and discovered with careful design of specific materials, they can create and control these orbitals with “a great variety of shapes and symmetries.” The results have potential applications in advanced optical technologies and quantum computing.

‘Whatever shape’

First author Marek Kozoň explained, “In textbook chemistry, electrons always orbit around the tiny atomic core at the centre of the orbital. So an electron orbital’s shape cannot deviate much from a perfect sphere. With photons, the orbitals can have whatever wild shape you design by combining different optical materials in designed spatial arrangements.”

The researchers conducted a computational study to understand how photons behave when they are confined in a specific 3D nanostructure consisting of tiny pores: a photonic crystal. These cavities are intentionally designed to have defects, creating a superstructure that isolates the photonic states from the surrounding environment.

Physicists and co-authors Willem L. Vos and Ad Lagendijk commented, “Given the rich toolbox in nanotechnology, it is much easier to design nanostructures with novel photonic orbitals than it is to modify atoms to achieve novel electronic orbitals and chemistry.”

Advanced optical technologies

Photonic orbitals are important for developing advanced optical technologies, such as efficient lighting, quantum computing, and sensitive photonic sensors. The researchers also studied how these nanostructures enhance the local density of optical states, which is important for applications in cavity quantum electrodynamics.

They found that structures with smaller defects reveal greater enhancement than those with larger defects. This makes them more suitable for integrating quantum dots and creating networks of single photons.

The research work is supported by the NWO-CSER program, project entitled “Understanding the absorption of interfering light for improved solar cell efficiency”; the NWO-JCER program, project “Accurate and Efficient Computation of the Optical Properties of Nanostructures for Improved Photovoltaics”; the NWO-GROOT program, project “Self-Assembled Icosahedral Photonic Quasicrystals with a Band Gap for Visible Light”; the NWO-TTW Perspectief program P15-36 “Free-Form Scattering Optics”; and the MESA+ Institute for Nanotechnology, section Applied Nanophotonics.