0000000000433287
AUTHOR
Worawut Khunsin
Self-assembled three-dimensional inverted photonic crystals on a photonic chip
Three dimensional photonic crystals (PhCs) exhibiting a full photonic band gap have high potential in optical signal processing and detector applications. However, the challenges in the integration of the 3D PhCs into photonic circuits have so far hindered their exploitation in real devices. This article demonstrates the fabrication of 3D PhCs exploiting the capillary directed self-assembly (CDSA) of monodisperse colloidal silica spheres, their inversion to silicon shells, and integration with silicon waveguides. The measured transmission characteristics agree with numerical predictions and provide strong indication of a full photonic band gap in the inverted 3D photonic crystals at wavelen…
Noise-Assisted Crystallization of Opal Films
International audience; An improvement of the crystal quality of opal fi lms self-assembled from polymer spheres in a moving meniscus using the agitation by white noise acoustic vibrations is demonstrated. A tenfold higher ordering of a hexagonal sphere packing in the (111) plane is achieved. This crystallization method, the mechanism of which is described in terms of the stochastic resonance, is a contrast to the widely used approach based on maintaining equilibrium conditions during the crystallization process. The precise quantifi cation of the incremental lattice order improvement as a function of acoustic noise intensity is achieved by calculating the probability of finding an opposite…
Transmission anisotropy in triple-film opal photonic crystals
Summary form only given: For photonic crystals (PhCs) to have successful impact on advancement of optical circuits and realisation of various functionalities, the incorporation of artificial defects into 3D PhCs is necessary. Opal films represent a convenient approach to the realisation of 3D PhCs. Taking into account the limited flexibility of the self-assembly, the first steps can be studies of planar defects in opals and hetero-opals. Characterisation of heteroPhCs should include the investigation of the dispersion of photonic bandgaps (PBG). While the dispersion of low-order PBGs in opal films is well known, the high order PBGs were hardly studied so far owing to high requirements to th…
2D photonic defect layers in 3D inverted opals on Si platforms
Dielectric spheres synthesised for the fabrication of self-organized photonic crystals such as opals offer large opportunities for the design of novel nanophotonic devices. In this paper, we show a hexagonal superlattice monolayer of dielectric spheres inscribed on a 3D colloidal photonic crystal by e-beam lithography. The crystal is produced by a variation of the vertical drawing deposition method assisted by an acoustic field. The structures were chosen after simulations showed that a hexagonal super-lattice monolayer in air exhibits an even photonic band gap below the light cone if the refractive index of the spheres is higher than 1.93.
Towards Si-based photonic circuits: Integrating photonic crystals in silicon-on-insulator platforms
In the context of Si-based photonics, we report on a strategy to integrate two optical components, a 3D photonic crystal light emitter and a waveguide, in a silicon-on-insulator patterned substrate. Self-assembled colloidal photonic crystals are produced with high crystalline quality and spatial selectivity. Plane wave expansion and finite-difference time-domain have been used to find suitable configurations for positioning emitters and waveguides. The first steps toward the realisation of these configurations are presented.