August 13, 2026 Theoretical framework expands directional light control beyond ordered crystal structures by Seoul National University edited by Sadie Harley, reviewed by Robert Egan Sadie Harley Scientific Editor Meet our editorial team Behind our editorial process Robert Egan Senior Editor Meet our editorial team Behind our editorial process Editors' notes This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: fact-checked peer-reviewed publication trusted source proofread The GIST Add as preferred source The directionality and symmetry of scattering vary according to the statistical correlations between refractive properties and absorption/amplification properties. ege of Engineering A research team has developed a new theoretical framework that can suppress light scattering in certain directions while enhancing it in others, even in irregularly arranged materials. The work extends research on controlling light scattering, which has traditionally centered on ordered crystal structures, into the realm of disordered systems.
Scattering—the process by which light is dispersed in multiple directions when it encounters matter—plays a critical role in determining the performance of a wide range of optical technologies, including anti-reflective coatings for eyeglasses and camera lenses, display diffusers, LiDAR sensors for autonomous vehicles, and optical communication components. Ultimately, the ability to precisely control scattering is a key determinant of competitiveness in optical technologies. The researchers, led by Professors Sunkyu Yu and Namkyoo Park of the Department of Electrical and Computer Engineering at Seoul National University College of Engineering, in collaboration with Professor Xianji Piao of the University of Seoul, proposed a theory they call "Non-Hermitian Statistical Crystallography," which considers not only refractive properties but also absorption and amplification.
Based on statistical correlations and rotational symmetries between refractive properties and absorption/amplification properties, the theory provides a conceptual framework for classifying and designing the scattering characteristics of open, disordered materials. The findings were published in Advanced Science. The rotational symmetry of statistical correlations is used to classify the scattering responses of open disordered materials and design their directionality. to hyperuniform disorder Until now, one of the principal approaches to precisely controlling light has been to use crystalline structures in which atoms or microstructures repeat at regular intervals.
The researchers, however, turned their attention to hyperuniform structures, which appear irregular at short distances but are distributed uniformly over larger scales. An analogy is an audience at a concert venue: people may appear to be standing randomly when viewed up close, yet if no section is either empty or excessively crowded, the overall density appears uniform from a distance. Similarly, hyperuniform structures are disordered locally but evenly distributed at larger scales.
Such structures scatter certain types of light only minimally. When this suppression of scattering extends across a certain range of wavelengths and directions, a phenomenon known as "stealthy hyperuniformity" emerges. Much like a stealth aircraft leaving almost no reflected signal at certain radar wavelengths, such a material effectively becomes "invisible" to light within specified ranges of wavelengths and directions.
Previous studies of hyperuniformity have primarily focused on materials in which energy is conserved. In real optical systems, however, light can be absorbed or amplified through externally supplied energy. Open wave systems in which energy can enter or leave in this manner are known as non-Hermitian systems.
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