Prof. Xiang Zhang's Research Group

Site Updated:
09/04/2008

Electronic Response Metamaterials

 

Objective

Engineer the Electro-Magnetic response at THz range by design the micro sub-structures of Meta-materials.

Background

For bulk metal materials, the free electron gas theory predicts the response to electromagnetic (EM) wave. The frequency dependent permittivity of metal is described by the Drude model as

 

Electromagnetic metamaterials, formed by artificial subwavelength components, are developed to provide designers new materials with properties that are not available in naturally existing materials. In this work, we demonstrate a THz plasmonic high pass filter consisting of high-aspect-ratio micron-sized metallic wire arrays. Realization of the plasmonic structure in THz ranges may lead new applications such as a high pass filter in the THz imaging.


Fig. 1: Environmental-SEM picture of the 2D cubic lattice fabricated by advanced mSL. Lattice constant a=120mm, wire radius r=15mm, wire length l=1mm
Fig. 2: Reflection signal from FTIR measurement. The solid line corresponding to the reflection signal for E filed parallel to the wire, and a rapid drop of the signal is observed above the plasma frequency (~0.7 THz).

Results

The structures are fabricated by a technique called micro stereo-lithography (uSL) developed in our lab. After uSL fabrication, a thin film of gold is sputtered uniformly on the polymer structures to ensure adequate conductivity. The reflectance measurements were performed using a Fourier transform infrared (FTIR) spectroscopy in the range of 0.6 THz to 6 THz with a near normal incident beam at room temperature. The polarized light was aligned either parallel (E field parallel to the wire) or perpendicular to the wires.

Representative Papers

Wu, D. Fang, N., Sun, C., and Zhang, X., 2003, “A THz plasmonic band pass filter”, Applied Physics Letter, Vol. 83, p. 201-203.

 

 
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