We report the design, fabrication, and characterization of a dual-band and polarization-insensitive metamaterial ab-sorber （MA）, which consists of periodically arranged fractal Koch curves acting as the top resonato...We report the design, fabrication, and characterization of a dual-band and polarization-insensitive metamaterial ab-sorber （MA）, which consists of periodically arranged fractal Koch curves acting as the top resonator array and a metallic ground plane separated by a dielectric spacer. Compared with conventional MAs, a more compact size and multi-frequency operation are achieved by using fractal geometry as the unit cell of the MA. Both the effective medium theory and the multi- reflection interference theory are employed to investigate the underlying physical mechanism of the proposed terahertz MA, and results indicate that the latter theory is not suitable for explaining the absorption mechanism in our investigated struc-ture. Two absorption peaks are observed at 0.226 THz and 0.622 THz with absorptivities of 91.3% and 95.6% respectively and good agreements between the full-wave simulation and experimental results are achieved.展开更多
A double-wire-grid polarizer was fabricated on both sides of a low-loss polythene film by simple electroplating and photolithographic micro-processing techniques. The performances of the polarizer were measured using ...A double-wire-grid polarizer was fabricated on both sides of a low-loss polythene film by simple electroplating and photolithographic micro-processing techniques. The performances of the polarizer were measured using a terahertz time-domain spectrometer （THz-TDS）. The transmittance is more than 70% and below 2% in the parallel and perpendicular directions of the polarizer, respectively. The extinction ratio is better than 22 dB in the broad frequency range of 0.5–3 THz, which is higher than the conventional free-standing polarizer in the high frequency region.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.60721001,51132003,and 61171047)the National Natural Youth Fund of China(Grant No.61001025)the National Programs for Science and Technology Development of Guangdong Province,China(Grant No.2010B090400314)
文摘We report the design, fabrication, and characterization of a dual-band and polarization-insensitive metamaterial ab-sorber （MA）, which consists of periodically arranged fractal Koch curves acting as the top resonator array and a metallic ground plane separated by a dielectric spacer. Compared with conventional MAs, a more compact size and multi-frequency operation are achieved by using fractal geometry as the unit cell of the MA. Both the effective medium theory and the multi- reflection interference theory are employed to investigate the underlying physical mechanism of the proposed terahertz MA, and results indicate that the latter theory is not suitable for explaining the absorption mechanism in our investigated struc-ture. Two absorption peaks are observed at 0.226 THz and 0.622 THz with absorptivities of 91.3% and 95.6% respectively and good agreements between the full-wave simulation and experimental results are achieved.
基金Supported by the National Basic Research Program of China under Grant No. 2007CB310407, the National Natural Science Foundation Grant No 50972023, and the International S＆T Cooperation Program of China under Grant No 2007DFR10250.
文摘A double-wire-grid polarizer was fabricated on both sides of a low-loss polythene film by simple electroplating and photolithographic micro-processing techniques. The performances of the polarizer were measured using a terahertz time-domain spectrometer （THz-TDS）. The transmittance is more than 70% and below 2% in the parallel and perpendicular directions of the polarizer, respectively. The extinction ratio is better than 22 dB in the broad frequency range of 0.5–3 THz, which is higher than the conventional free-standing polarizer in the high frequency region.
