Prototyping of Terahertz Metasurface by One-Step Lithographically Defined Templating

To bypass the sophisticated procedure in existing techniques to produce the terahertz (THz) metasurface filter, a one-step lithographically defined templating method is proposed for rapid prototyping. Essentially, a simplified photolithography process is exploited and optimized first to release one freestanding template perforated with desired features, without any sacrificial layer or external force. The key idea is to impart an adequate degree of hydrophobicity to substrate to tune adhesion between substrate and template for a spontaneous release. Then, the template-directed metallization by electroless plating gives rise to an intact freestanding metal mesh framework of THz metasurface filter. Spectral characterization by the THz frequency-domain spectroscopy shows good spectral selection behavior, which agrees adequately well with the numerical simulation by HFSS.