## Experimental evidence for Band Gap Formation and Anderson localization regimes for microwaves in hyperuniform 2D materials

Geoffroy Aubry
geoffroy.aubry@unifr.ch
Département de Physique, Université de Fribourg, Switzerland

Recently, it has been shown that disordered dielectrics can show a photonic band gap in the presence of structural correlations [1], but 30 years after John's seminal proposal on the interplay between the photonic pseudo band gap in disordered photonic crystals and Anderson localization [2], a controlled experimental study of the transport properties in between ordered and disordered states is still lacking. In this talk, I present new experimental and numerical results obtained for a 2D system composed of high index dielectric cylinders in air [3] placed according to stealthy hyperuniform point patterns [1]. Measurements are performed in the microwave range (1 to 10 GHz). In addition to the (local) density of states and the Thouless conductance, we can access experimentally the field amplitude which allows us to unambiguously visualize single eigenmodes in finite size open systems for all the transport regimes such as stealthy-transparent, diffusion, Anderson-localization and the band gap [4], as a function of the degree of stealthiness $\chi$. Our observations are supported by the analysis of the spreading of the wave in the time domain.

[1] M. Florescu, S. Torquato, and P. J. Steinhardt, Designer disordered materials with large, complete photonic band gaps PNAS 106, 20658 (2009)

[2] S. John, Strong localization of photons in certain disordered dielectric superlattices, Phys. Rev. Lett. 58, 2486 (1987).

[3] D. Laurent et al. Localized Modes in a Finite-Size Open Disordered Microwave Cavity, Phys. Rev. Lett. 99, 253902 (2007).

[4] L. Froufe-Pérez et al., Band gap formation and Anderson licalization in disordered photonic materials with structural correlations PNAS 114, 9570 (2017).