Photonic revolution: Narwhal-shaped wave miniaturizes light

Electronics

Technological Innovation Website Editorial Team - 06/11/2025

The secret to miniaturizing light computers lies in a narwhal-shaped wave function, which allows for spatial confinement in a proper electromagnetic mode and directly determines the strength of light-matter interactions. [Image: Wen-Zhi Mao et al. - 10.1186/s43593-025-00104-x]

Light-based computing

Photonic computing , with its processors that use photons instead of electrons , has already largely demonstrated its advantages in terms of speed and energy efficiency compared to electronic computers.

However, there are still challenges to overcome before you can buy a photonic cell phone or notebook: Optical components don't compete with semiconductor electronics when it comes to miniaturization .

The reason is fundamental: Heisenberg's uncertainty principle links the spatial confinement of light to its wavelength, which in the visible and near-infrared can be up to a thousand times longer than the wavelength of electrons. This incompatibility has kept photonic chips bulky.

Plasmonics offers a way to circumvent the barrier, using metals to compress light into volumes below the wavelength. But metals dissipate energy in the form of heat, generating a need for compensation that hinders progress toward efficient, large-scale integration of light computers.

Characteristics of the narwhal wave and its mode of generation. [Image: Wen-Zhi Mao et al. - 10.1186/s43593-025-00104-x]

Narwhal-shaped wave

Hopes for a definitive boost to miniaturizing light-based computing began to emerge last year when a team from Peking University in China developed a singular scattering equation, a new theoretical framework showing how light can be confined to extreme scales in dielectric (insulating, or non-conductive) materials without loss.

By relying exclusively on dielectric materials, the approach avoids ohmic losses, paving the way for a new generation of compact and energy-efficient photonic devices.

Now, the same team has gone further in its understanding of the phenomenon, discovering that the extraordinary confinement made possible by the singular dispersion equation emerges from a new class of electromagnetic eigenmodes, special wave functions with a narwhal-shaped profile. The wave assumes a profile reminiscent of the narwhal, or sea unicorn, a toothed whale that has a long, straight, helical tusk that looks like a horn, but is actually an elongated upper left canine tooth.

These wave modes combine local power law strengthening with global exponential decay, allowing electromagnetic fields to concentrate and compress far beyond the conventional limits dictated by wavelength.

With this understanding, the team then found themselves in possession of all the necessary tools to demonstrate the effect in practice.

The narwhal-shaped wave is produced by dielectric nanolasers using nanoantennas with atomic-scale dimensions. [Image: Yun-Hao Ouyang et al. - 10.1038/s41586-024-07674-9]

Miniaturization of photonics

Wen-Zhi Mao and his colleagues then designed, built, and experimentally demonstrated the operation of a three-dimensional dielectric resonator capable of confining waves by subdiffraction in all three spatial dimensions.

Using near-field scanning measurements, they directly observed the narwhal-shaped wave functions, clearly capturing their growth near the singularity, following the power law, and exponential decay at larger intervals. The volume achieved is minuscule, only 5 × ^{10⁻⁷ λ³} - lambda represents the wavelength of light.

The experiment proves that the singular dispersion equation gives rise to narwhal-shaped wave functions, exotic modes that capture light at extreme scales in lossless dielectrics, inaugurating what the team calls "singulonics," a new nanophotonic paradigm that allows the confinement of light in dimensions much smaller than the wavelength, as well as the control of this light without losses due to dissipation.

This breakthrough promises to finally boost ultra-efficient information processing, opening new avenues in quantum optics and microscopy , expanding the reach of super-resolution imaging. In the latter case, the team has already used its experiment to demonstrate a new near-field scanning optical microscopy technique, which they dubbed the singular optical microscope, exhibiting an unprecedented spatial resolution of λ/1000.

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