Light travels well in few-atom-thick waveguide

Author: EIS Release Date: Aug 22, 2023

The University of Chicago has built optical waveguides only three atoms thick using molybdenum disulphide, and found them to be an efficient way to transfer light over chip-scale distances.

 

UChicago JiwoongPark 2d light guide photoByJeanLachat

“We were surprised by how powerful this super-thin crystal is,” said University of Chicago professor Jiwoong Park, “not only can it hold energy, but deliver it a thousand times further than anyone has seen in similar systems. The trapped light behaved like it is travelling in a 2D space.”

 

As electrons and photons can both be treated as wave-like entities, the researchers borrowed maths created to describe electron behaviour.

 

 

“The extreme thinness provides a light-trapping mechanism analogous to a δ-potential well in quantum mechanics and enables the guided waves that are essentially a plane wave freely propagating along the in-plane, but confined along the out-of-plane, direction of the waveguide,” according to ‘Wafer-scale δ waveguides for integrated two-dimensional photonics‘, a paper which describes the work in Science.

 

 

By patterning the MoS2 and adding various dielectric and metal structures: refraction, focusing and intensity modulation were demonstrated, and gratings and inter-connectors were built.

 

Photons in the waveguide are affected by the external environment.

 

“For example, say you had a sample of liquid, and you wanted to sense whether a particular molecule was present,” said Park. “You could design it so that this waveguide travels through the sample, and the presence of that molecule would change how the light behaves.”

 

Intra-chip communication is another potential application, and the technique is, in principal, applicable to some other 2D materials, said the university.