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Using a new class of isotropic disordered photonic bandgap material, we demonstrate freeform photonics waveguides with arbitrary shapes and multi-channel frequency splitters with versatile tuning abilities, useful for signal processing and all-optical circu it applicat ions. ©2012 Optical Society of America OCIS codes: 130.5296, 130.7408, 160.5293, 160.5298 Inside photonic band gap (PBG) materials, light with selected frequencies can be confined and directed along chosen paths of line defects and around sharp corners [1], which is important for a large range of technological developments in telecommunication industry, laser engineering, optical computing, spectroscopy, etc [2]. However, in conventional PBG materials, periodic photonic crystals, only a limited number of rotational symmetries are allowed. The orientations of channels cut in photonic crystals for light guiding are strictly limited by the crystal symmetries, a disadvantage for potential applications.Contradicting the long standing intuition that periodicity or long-range translational order is required in photonic band gap formation, a new class of disordered hyperuniform materials was predicted to possess sizeable and isotropic photonic band gaps [3]. Recently, we have experimentally observed isotropic PBG in these disordered materials [4]. In these isotropic disordered structures there are no preferential symmetry directions; hence it becomes possible to construct freeform channels with arbitrary shapes and bends in them [5]. We also demonstrated that line defects and point defects in these structures can be flexibly decorated to produce sharp resonant structures useful for filtering [5].In terms of signal processing, photonic devices have many advantages over electronics, especially the large bandwidth. Since photons do not interact with each other, light signals of different frequencies can travel independently and simultaneously within the same channel. Hence, very compact frequency splitter becomes essential for large scale all-optical circuit applications. Since this new class of hyperuniform PBG material is isotropic and disordered, it provides the combined advantages of freeform direction choices not restricted by crystalline symmetries and flexible resonant tuning abilities. These advantages will enable the design of complex photonic circuits, for example, compact and tunable frequency splitters.In this paper, we report the first experimental demonstrations of freeform wave-guiding through channels of arbitrary shapes, as well as tunable multi-channel frequency splitting of electromagnetic waves in 2D hyperuniform isotropic disordered PBG materials.The 2D isotropic hyperuniform disordered PBG material constructed for this study consists of a network of Al 2 O 3 cylinders, arranged at a hyperuniform disordered point pattern [3,5]. There is neither Bragg scattering nor long-range translational order in this structure. It was argued that hyperuniformity, combined with uniform local topology and short-range geometric order can exp...

Abstract:We introduce novel architecture for cavity design in an isotropic disordered photonic band gap material. We demonstrate that point-like defects can support localized modes with different symmetries and multiple resonant frequencies, useful for various applications. ©2012 Optical Society of America OCIS codes: 130.5296, 130.7408, 160.5293, 160.5298 Since photonic band gap (PBG) materials were first introduced, optical cavities (point defects in PBG materials) have attracted extensive attention due to their ability to trap light of certain frequencies within extremely small mode volume. Better understanding and control of frequency, location, and symmetry order of cavity modes inside the PBG will have an important impact on designing of novel sensors, filters, lasers, optical switches, and optical circuits [1].Recently, it has been predicted and observed that hyperuniform disordered dielectric structures, which do not possess long-range translational order like crystals do, can also have complete PBGs [2][3][4]. More importantly the structures and PBGs are isotropic, not limited to crystalline rotational symmetry, hence allowing novel and flexible architecture of cavity (point defects) and wave-guide (line defects) design.According to recent simulation studies by Florescu et al, introducing a point defect by removing a single dielectric cylinder from a 2D hyperuniform PBG structure, results in a localized cavity mode with monopole symmetry [5]. The electric field oscillation pattern was predicted to extend 1-2 cell widths into the surrounding structure ( Figure 1). When a defect dielectric cylinder of increasing radius is used to replace a regular one, the electric field of the localized cavity modes would oscillate with changing symmetries. For every symmetry order, such as monopole, dipole, quadrupole, hexapole and octopole, it was observed that an increase in defect cylinder radius will introduce higher resonant frequencies inside the PBG region.Our experimental structure is assembled using Al 2 O 3 cylindrical rods (r = 2.5mm, h = 10cm), inserted into a platform of a hyperuniform disordered pattern with 1cm deep slots. The average cell size (spacing between rods) is a = 13.3 mm. The structure has a TM polarization PBG from 9.2 to 10.7 GHz. Cavities are easily generated and changed in this structure by removing rods to create voids and placing bundled clusters of rods into the voids. We use horn antennas attached to a microwave vector network

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We report experimental and simulation results for low-loss wave-guiding in Si-based hyperuniform disordered photonic bandgap materials at infrared wavelengths. These results pave the way for deploying disordered photonic solids in integrated photonic circuits. © 2014 Optical Society of America