Abstract-Tunable metamaterial filter for optical communication in the terahertz frequency range

Wei Yang and Yu-Sheng Lin

Schematic drawing of metamaterial-based TTF. (a) 3D illustration of metamaterial-based TTF. (b) Top-view and (c) 3D illustrations of TTF unit cell and the geometrical parameters. The outer radius (R) is 4.19 µm. The inner radius (r) is 3.89 µm. The line width of the structure (w) is 300 nm. The gap between the ring-shaped and cross-shaped structures (g) is 300 nm. The thickness of metamaterial-based TTF (d) is 300 nm. The height between the bottom ring-shaped and the top cross-shaped structures (h) is variable. (d) Schematic drawing of the proposed TTF for indoor THz wireless communication system application. (e) Fabrication process flow of proposed TTF along AA’ line in (a). (i) The deposition of Au thin-film with 300 nm in thickness for the bottom ring-shaped nanostructure of TTF by using the lift-off process. (ii) The deposition of SiO2 and Si3N4 thin-films by using PECVD sequentially. (iii) The deposition of Au thin-film with 300 nm in thickness for the top cross-shaped nanostructure of TTF by using the lift-off process. (iv) Si3N4 thin-film is patterned by using RIE processes. (v) The microstructures are released by using vapor HF.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-28-12-17620

We present a design of a tunable terahertz (THz) filter (TTF) used in an indoor communication system. The unit cell of TTF is composed of ring-shaped and cross-shaped nanostructures. By utilizing the micro-electro-mechanical system (MEMS) technique to modify the height between the ring-shaped and cross-shaped nanostructures in the incident transverse electric (TE) mode, the resonant frequencies can be tuned from 0.530 THz to 0.760 THz, which covers an atmospheric window from 0.625 THz to 0.725 THz for indoor wireless optical communication applications. This design of TTF provides an effective approach to select and filter specific signals. It makes the data processing more flexible at the transmission end of the communication system. Furthermore, such a TTF design can be realized the commercialization of communication system components due to its integrated circuit (IC) process compatibility, miniaturization and high flexibility.

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