Phononic crystals, artificial materials with periodically arranged scattering centers, were introduced more than two decades ago as the elastic waves analogue of photonic crystals. These materials, either in two or three dimensions, can exhibit large frequency regions of prohibited propagation of elastic waves, the so-called phononic band gaps (PBGs). On the other hand, typical elastic wave propagation in random structures is associated with diffusion, or in extreme situation with localization, and random structures do not exhibit band gaps. Here, we introduce a new class of structurally disordered phononic structures, hyperuniform disordered phononic structures (HDPS) that exhibit large elastic band gaps. These structures are created from initially arbitrary point patterns by imposing hyperuniform correlations among the points and finally decorating them with a specific scatterers, so that the structure factor becomes isotropic and vanishes for all k-vectors within a specific radius. The disorder can smoothly be tuned to produce structures ranging from totally random to fully periodic by adjusting a single parameter. Such amorphous structures exhibit large band gaps, comparable to the ones found in the periodic counterparts, ballistic and diffusive propagation depending on the modes frequency and a large number of localized modes near the band edges. We discuss the formation of high-Q cavity modes and waveguides with 100% transmission in these disordered structures in the GHz regime. Such phononic-circuit architectures are expected to have a direct impact on integrated micro-electro-mechanical filters/modulators for wireless communications and acoustic-optical sensing devices.
Hyperuniform disordered photonic structures/solids (HUDS) are a new class of photonic solids, which display large, isotropic photonic band gaps (PBG) comparable in size to the ones found in photonic crystals (PC). The existence of large band gaps in HUDS contradicts the long-standing intuition that Bragg scattering and long- range translational order is required in PBG formation, and demonstrates that interactions between Mie-like local resonances and multiple scattering can induce on their own PBGs. HUDS combine advantages of both isotropy due to disorder (absence of long range two-point correlations) and controlled scattering properties from uniform local topology due to hyperuniformity (constrained disorder). In this paper we review the photonic properties of HUDS including the origin of PBGs and potential applications. We address technologically realisable designs of HUDS including localisation of light in point-defect-like optical cavities and the guiding of light in free-form PC waveguide analogues. We show that HUDS are a promising general-purpose design platform for integrated optical micro-circuitry, including active devices such as optical microcavity lasers and modulators.
Hyperuniform disordered solids are a new class of designer photonic materials with large isotropic band gaps
comparable to those found in photonic crystals. The hyperuniform disordered materials are statistically isotropic and
possess a controllable constrained randomness. We have employed their unique properties to introduce novel
architectures for optical cavities that achieve an ultimate isotropic confinement of radiation, and waveguides with
arbitrary bending angles. Our experiments demonstrate low-loss waveguiding in submicron scale Si-based hyperuniform
structures operating at infrared wavelengths and open the way for the realization of highly flexible, disorder-insensitive
optical micro-circuit platforms.