Tunable high-index photonic glasses

Abstract

Materials with extreme photonic properties such as maximum diffuse reflectance, high albedo, or tunable band gaps are essential in many current and future photonic devices and coatings. While photonic crystals, periodic anisotropic structures, are well established, their disordered counterparts, photonic glasses (PGs), are less understood despite their most interesting isotropic photonic properties. Here, we introduce a controlled high index model PG system. It is made of monodisperse spherical TiO${}_2$ colloids to exploit strongly resonant Mie scattering for optimal turbidity. We report spectrally resolved combined measurements of turbidity and light energy velocity from large monolithic crack-free samples. This material class reveals pronounced resonances enabled by the possibility to tune both the refractive index of the extremely low polydisperse constituents and their radius. All our results are rationalized by a model based on the energy coherent potential approximation, which is free of any fitting parameter. Surprisingly good quantitative agreement is found even at high index and elevated packing fraction. This class of PGs may be the key to optimized tunable photonic materials and also central to understand fundamental questions such as isotropic structural colors, random lasing or strong light localization in 3D.

arXiv commentMain text: 8 pages, 4 figures; Supporting Information: 5 pages, 5 figures

References in corpus (10)

• Observation of the critical regime near Anderson localization of light
• Biomimetic isotropic nanostructures for structural coloration
• Absence of Anderson localization of light in a random ensemble of point scatterers
• Direct determination of the transition to localization of light in three dimensions
• Can 3D light localization be reached in "white paint"?
• Photonic glass for high contrast structural color
• Resonant transport and near-field effects in photonic glasses
• Tuning random lasing in photonic glasses
• Longitudinal optical fields in light scattering from dielectric spheres and Anderson localization of light
• Position-dependent radiative transfer as a tool for studying Anderson localization: Delay time, time-reversal and coherent backscattering

Cited by in corpus (4)

• Light in correlated disordered media
• Colors from correlated disordered photonic systems -- can we outperform nature?
• Effects of multiple scattering on angle-independent structural color in disordered colloidal materials
• Magnetic field effects on one-dimensional Anderson localization of light