Digital design of multimaterial photonic particles

Significance We present an approach for the facile fabrication of dielectric particles having the size of an optical wavelength yet endowed with a complex multimaterial internal nanoscale architecture. This methodology amounts to “digitally designing” the particle by precisely allocating the desired material at prescribed coordinates within the 3D volume of the particle. The digital design of such a photonic particle enables sophisticated strategies for controlling light scattering. As an example, without changing the size of a core–shell particle, its optical scattering strength can be tuned above or below that afforded by its constitutive materials by changing the core–shell diameter ratio. This work may lead to the development of new optical coatings and paints with exotic functionality. Scattering of light from dielectric particles whose size is on the order of an optical wavelength underlies a plethora of visual phenomena in nature and is a foundation for optical coatings and paints. Tailoring the internal nanoscale geometry of such “photonic particles” allows tuning their optical scattering characteristics beyond those afforded by their constitutive materials—however, flexible yet scalable processing approaches to produce such particles are lacking. Here, we show that a thermally induced in-fiber fluid instability permits the “digital design” of multimaterial photonic particles: the precise allocation of high refractive-index contrast materials at independently addressable radial and azimuthal coordinates within its 3D architecture. Exploiting this unique capability in all-dielectric systems, we tune the scattering cross-section of equisized particles via radial structuring and induce polarization-sensitive scattering from spherical particles with broken internal rotational symmetry. The scalability of this fabrication strategy promises a generation of optical coatings in which sophisticated functionality is realized at the level of the individual particles.