Tunable optical angular selectivity in hyperbolic metamaterial via photonic topological transitions

An ultra-narrow angular optical transparency window based on photonic topological transition (PTT) is theoretically and numerically investigated in a low-loss hyperbolic metamaterial (HMM) platform, which consists of aligned metallic nanowires embedded indielectric host matrices. Our results indicate that, near the transition point of PTT, the designed system exhibits high-efficiency optical angular selectivity close to normal incidence by tailoring the topology of metamaterial's equi-frequency surface (EFS). Moreover, the operating wavelength (λ0) is flexibly tunable by selecting appropriate material and geometrical parameters, which provides significant guidance for the later experimental design. Our method is further applied to super-resolution imaging, with a resolution of at least λ0/4 and over a significant distances (>12λ0). The HMM-supported angularly selective system could find promising applications for high-efficiency light manipulation and lensless on-chip imaging.