Enhanced complete photonic bandgap in a moderate refractive index contrast chalcogenide-air system with connected-annular-rods photonic crystals

Abstract

Connected-annular-rods photonic crystals (CARPCs) in both triangular and square lattices are proposed to enhance the two-dimensional complete photonic bandgap (CPBG) for chalcogenide material systems with moderate refractive index contrast. For the typical chalcogenide-glass-air system with an index contrast of 2.8:1, the optimized square lattice CARPC exhibits a significantly larger normalized CPBG of about 13.50%, though the use of triangular lattice CARPC is unable to enhance the CPBG. It is almost twice as large as our previously reported result [IEEE J. Sel. Top. Quantum Electron. 22, 4900108 (2016)]. Moreover, the CPBG of the square-lattice CARPC could remain until an index contrast as low as 2.24:1. The result not only favors wideband CPBG applications for index contrast systems near 2.8:1, but also makes various optical applications that are dependent on CPBG possible for more widely refractive index contrast systems.

Structurally engineered colloidal quantum dot phosphor using TiO2 photonic crystal backbone

“…Figure 1b–e shows the band structures calculated for the four different PhC phosphor platforms: Si 3 N 4 backbone with a wavy CQD surface (SiN-W), Si 3 N 4 backbone with the planar CQD surface (SiN-P), TiO 2 backbone with a wavy CQD surface (TiO-W), and TiO 2 backbone with the planar CQD surface (TiO-P). The most distinct change induced by replacing the backbone material from Si 3 N 4 to TiO 2 (that is, increased index contrast) is the opening and widening of the photonic bandgap 29 , 30 . Consequently, more pronounced PhC effects are expected 31 – 35 .…”

Self-assembly of POSS–Polystyrene Bottlebrush Block Copolymers on an Angle-Robust Selective Absorber for Enhancing the Purity of Reflective Structural Color

“…The color purity was heavily impacted by the long-range order and macroscopic orientation of the nanostructure, and the nanostructures were mediated by controlling the composition and segregation strength of the side chains. − ,− Despite the successes achieved in full color-displayed PCs via self-assembly of the BBCP, to date, there are no reports on the effect of optical substrates on the self-assembly and optical properties of BBCP-based PCs. The addition of highly absorbing dopants can compensate for the degraded color saturation and low reflectance of BBCP-based 1D PCs, and it is involved in modulating photonic band gaps and increasing the refractive index contrast. − However, a combinational process with an absorbing dopant and a BBCP-based PC has been unexplored.…”

Vivid colours in hyperuniform complex-index photonic structures by resonant interference of photonic band gaps and optical band gaps

“…While these low optical properties can be enhanced by increasing the refractive index contrast, the choice of material pair is quite limited. 25,26 Instead of synthesizing photonic structures with new materials, in this study, we employed a small amount of complex index dopants in HPSs, which are made of conventional dielectric materials such as SiO 2 . With the addition of a small amount of dopants (<1%), the reectivity and the colour expression range of HPSs increased by 100% and 600%, respectively, compared with that of undoped HPSs.…”