Manipulating terahertz radiation using novel metamaterials towards functional passive and active devices

Abstract

Scope and Method of Study: The objective of this study is to explore the fundamental physics in novel metamatrials functioning in THz region, and to develop passive and active functional devices, such as filters, switch/modulators, waveguides and sensors functioning in the terahertz regime. Such metamaterial structures were fabricated by using microelectronic lithography technique. The transmission and dispersion properties of the metamaterials were systematically investigated by using terahertz time-domain spectroscopy. Numerical simulations were carried out to further verify and reveal the experiment results.

Findings and Conclusions: We demonstrated that membrane metamaterials could resolve the limitations encountered in planar metamaterials fabricated on conventional substrates, and are particularly advantageous for developing cost-effective and high-performance devices, such as high-Q THz filter and disposable THz sensors. Moreover, we proposed that anisotropic metamaterials could be used to trap and harvest THz radiations in designed metamaterials waveguides. This research will lead to broad range applications, including optical delay-lines, ultra-broadband absorbers, sensitive detectors and optical sensor benefited from the enhanced light-matter interaction in metamaterial waveguides. In order to extend the tunability of metamaterials, we demonstrated that surface modes supported by the membrane metamaterials can be incorporated into the design of broadband tunable devices, showing great potential in practical applications, such as broadband filters and phase shifters functioning in the far-infrared region. In our latest research, it is found that micro-textiles can act as excellent artificial electromagnetic materials. On the other hand, a textile consisting of periodic networks of microfibers can be a pump-free microfluidic system because of the fluidic flow driven by the capillary force of fibers. We successfully combine the electromagnetic textile materials and microfluidic systems together, and make it functioning in the THz region. This research opens a door in developing functional metamatrials and new THz optofluidic systems. Importantly, a new microfluidic sensing platform is demonstrated which is benefited from the strong light-fluid interaction in textile metamaterials, showing great potential for cost-effective and high performance sensing platform useful in chemistry, biology and medicine applications.