https://scitechdaily.com/seemingly-impo ... e_vignette
https://www.nature.com/articles/s41467-022-33874-w
Until recently, physicists widely believed that it was impossible to compress light below the so-called diffraction limit, except when utilizing metal nanoparticles, which also absorb light. As a result, it seemed to be impossible to compress light strongly in dielectric materials like silicon, which are essential for information technologies and had the significant advantage of not absorbing light. Interestingly, it was theoretically shown that the diffraction limit does not apply to dielectrics back in 2006. However, no one has been able to demonstrate this in the actual world due to the fact that it requires such complex nanotechnology that no one has yet been able to create the required dielectric nanostructures.
A research team from the Technical University of Denmark has created a device known as a “dielectric nanocavity” that successfully concentrates light in a volume 12 times smaller than the diffraction limit. The finding is groundbreaking in optical research and was recently published in the journal Nature Communications.
Optical nanocavities are structures that have been specially designed to retain light so that it does not travel normally but is tossed back and forth as if two mirrors were facing each other. The closer the mirrors are to one other, the more intense the light between them gets. For this experiment, the researchers created a bowtie structure, which is particularly effective in squeezing photons together due to its unique shape.
The nanocavity is made of silicon, the dielectric material on which most advanced modern technology is based. The material for the nanocavity was developed in cleanroom laboratories at DTU, and the patterns on which the cavity is based are optimized and designed using a unique method for topology optimization developed at DTU. Initially developed to design bridges and aircraft wings, it is now also used for nanophotonic structures.
The energy consumption for computers and data centers continues to grow, and there is a need for more sustainable chip architectures that use less energy. This can be achieved by replacing electrical circuits with optical components. The researchers’ vision is to use the same division of labor between light and electrons used for the Internet, where light is used for communication and electronics for data processing. The only difference is that both functionalities must be built into the same chip, which requires that the light be compressed to the same size as the electronic components. The breakthrough at DTU shows that it is, in fact, possible.