Shrinking light: The waveguide pattern allows for highly narrowed subnanometer optical fields

Imagine shrinking light to the size of a tiny water molecule, unlocking a world of quantum possibilities. This has been a long-held dream in the realms of light science and technology. Recent advances have brought us one step closer to achieving this incredible feat, as researchers at Zhejiang University have made groundbreaking advances in confining light to sub-nanometer scales.

Traditionally, there have been two approaches to localizing light beyond its typical diffraction limit: dielectric confinement and plasmon confinement. However, challenges such as precision manufacturing and optical loss have hampered the confinement of optical fields to levels below 10 nanometers (nm) or even 1 nm. But now a new waveguide scheme has been introduced Advanced photonics promises to unlock the potential of subnanometer optical fields.

Imagine this: Light travels from an ordinary optical fiber, taking a transformative journey through a cone of fiber, and finds its destination in a pair of bonded nanowires (CNP). Inside the CNP, light transforms into a unique nano-slit mode, generating a confined optical field that can be as tiny as a mere fraction of a nanometer (about 0.3 nm). With an astonishing efficiency of up to 95% and a high peak-to-bottom ratio, this new approach opens up a whole new world of possibilities.

The new waveguide scheme extends its reach into the mid-infrared spectral range, further pushing the boundaries of the nano-universe. Optical confinement can now reach an astonishing scale of approximately 0.2 nm (/20000), providing even more opportunities for exploration and discovery.

Professor Limin Tong of Zhejiang University’s Nanophotonics Group notes, ‘Unlike previous methods, the waveguide pattern is presented as a linear optical system, bringing a number of advantages. It allows both broadband and pulsed operation It is ultrafast and allows for the combination of multiple sub-nanometer optical fields. The ability to engineer spatial, spectral and temporal sequences within a single output opens up endless possibilities.”

This video summary includes an animated demonstration by the authors.

The potential applications of these discoveries are staggering. An optical field so localized that it can interact with individual molecules or atoms promises advances in light-matter interactions, super-resolution nanoscopy, atom/molecule manipulation and ultrasensitive sensing. We stand on the brink of a new age of discovery, where the smallest realms of existence are within our reach.