Engineered disorder and light propagation in a planar photonic glass.
The interaction of light with matter strongly depends on the structure of the latter at wavelength scale. Ordered systems interact with light via collective modes, giving rise to diffraction. In contrast, completely disordered systems are dominated by Mie resonances of individual particles and random scattering. However, less clear is the transition regime in between these two extremes, where diffraction, Mie resonances and near-field interaction between individual scatterers interplay. Here, we probe this transitional regime by creating colloidal crystals with controlled disorder from two-dimensional self-assembly of bidisperse spheres. Choosing the particle size in a way that the small particles are transparent in the spectral region of interest enables us to probe in detail the effect of increasing positional disorder on the optical properties of the large spheres. With increasing disorder a transition from a collective optical response characterized by diffractive resonances to single particles scattering represented by Mie resonances occurs. In between these extremes, we identify an intermediate, hopping-like light transport regime mediated by resonant interactions between individual spheres. These results suggest that different levels of disorder, characterized not only by absence of long range order but also by differences in short-range correlation and interparticle distance, exist in colloidal glasses.
Institute of Particle Technology, Friedrich-Alexander University Erlangen-Nürnberg, Haberstr. 9a, 91058 Erlangen, Germany.|Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany.|Ioffe Physical Technical Institute, 194021, Politekhnicheskaya ul., 26, St. Petersburg, Russia.
Sergei G
SG
Romanov
Center for Physical Sciences and Technology, Savanoriu Ave., 231, LT-02300, Vilnius, Lithuania.
Sergej
S
Orlov
Institute of Optics, Information and Photonics, University of Erlangen-Nuremberg, Haberstr. 9a, 91058 Erlangen, Germany.
Daniel
D
Ploss
FH Bingen, Berlinstraße 109, 55411 Bingen am Rhein, Germany.
Clemens K
CK
Weiss
Institute of Particle Technology, Friedrich-Alexander University Erlangen-Nürnberg, Haberstr. 9a, 91058 Erlangen, Germany.|Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany.
Nicolas
N
Vogel
Institute of Solid State Theory and Optics, FSU Jena, Max-Wien-Platz 1, 07743 Jena, Germany.
Ulf
U
Peschel