Bricked Subwavelength Gratings: A Tailorable On‐Chip Metamaterial Topology

Abstract

Integrated metamaterials are redefining the capabilities of silicon photonic chips. In providing lithographic control over dielectric permittivity, dispersion and anisotropy, they are enabling photonic devices with unprecedented performance. However, the implementation of these materials at telecom wavelengths often requires a fabrication resolution of the order of 100 nm and below, pushing current wafer‐scale fabrication technology to its limits and hindering the widespread exploitation of on‐chip metamaterials. Herein, a subwavelength grating metamaterial with bricked topology is proposed, that provides lithographic control over the metamaterial dispersion and anisotropy using a single etch Manhattan‐like geometry with pixel dimensions up to 150 × 150 nm2, thereby easing the path toward fabrication at wafer‐scale. The behavior of these structures as biaxial crystals is analytically shown, validating their use in high performance on‐chip beam‐splitters. Through engineering of the metamaterial anisotropy tensor, the splitters are shown to exhibit sub‐decibel insertion losses and imbalance over a 400 nm design bandwidth, via 3D FDTD simulations. The excellent device performance is demonstrated over a 140 nm bandwidth, limited by the measurement setup.

Imidazole ionic liquids-based ultra-broadband metamaterial absorbers from cross-architecture design

“…By modulating the liquid's * Author to whom any correspondence should be addressed. shape and thickness, absorption bands can be controlled, offering an advantage over solid-based MMAs [3][4][5], which often rely on electromagnetic resonance [6,7] enabled by programmable controls [7,8], leading to the widespread application in photoelectric conversion, on-chip system and photonic and plasmonic metasensors [9][10][11]. This adaptability paves the way for potential applications in optically transparent absorbers and transparent energy harvesting systems [12][13][14].…”

Experimental characterization of an ultra-broadband dual-mode symmetric Y–junction based on metamaterial waveguides

“…Subwavelength engineering has become a strong design method for the realization of integrated silicon photonics components, including fiber-chip couplers [41], reconfigurable filters [46] and gradient-index lenses [47]. SWG metamaterials have also been successfully applied to several power splitters such as asymmetric directional couplers [48], three-guide directional couplers [49], inverse tapers [45,50], slot adiabatic waveguides [51], MMI devices [52][53][54], waveguide crossings [55] and Y-junctions [56]. Recently, we proposed an architecture for a highperformance and fabrication-tolerant SWG Y-junction [57].…”

Dielectric Metasurfaces Enabled Ultradensely Integrated Multidimensional Optical System

“…[23][24][25] Especially, on-chip dielectric metasurfaces [26,27] have compact footprint, low loss, and broad bandwidth to achieve multifunctional photonic integrated devices. [28][29][30][31] Inverse-designed method, enabling to manipulate the optical field at subwavelength scale for on-chip dielectric metasurfaces, has become a powerful design tool for superminiature photonic devices in recent years. [32][33][34] Usually, the length of inverse-designed photonic devices is only several micrometers.…”