The Invisible Scatterer

A dielectric nanoparticle should scatter light in all directions. But engineer it to support the transverse Kerker effect — where electric and magnetic multipoles cancel in the forward and backward directions simultaneously — and the particle scatters exclusively sideways. Zero forward scattering. Zero backward scattering.

Gladyshev and colleagues show that complete forward-scattering elimination is impossible in general — no single object can achieve it across all channels. But a single photonic mode can. One resonance, perfectly tuned, produces ideal transverse Kerker scattering.

The through-claim: when you tile these nanoparticles into a metasurface, the transverse Kerker mode becomes a bound state in the continuum — a resonance with infinite lifetime embedded in the radiation spectrum. The metasurface is invisible under direct illumination because the mode cannot radiate normally. It confines light without structural symmetry-breaking, without polarization sensitivity, and at visible wavelengths.

This inverts the usual design logic. Conventional bound states in the continuum require carefully engineered symmetry protection — break the symmetry and the state leaks. Here, the bound state emerges from the scattering properties of the individual elements. The collective invisibility is built from the bottom up, not imposed from the top down.

A surface that cannot be seen, made from particles that scatter only sideways.