Monday, 23 July 2012

Surface relief structures for a flexible broadband terahertz absorber



Dong-Hyun Kim,1 Dae-Seon Kim,1 Sehyun Hwang,2 and Jae-Hyung Jang1,2,3,*

1School of Information and Communications, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, South Korea
2Research Institute for Solar and Sustainable Energies, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, South Korea
3Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, South Korea


Abstract

Terahertz (THz) absorbers with surface relief structures (SRSs) were designed and fabricated on a flexible polydimethylsiloxane(PDMS) substrate by using a stamping method. The silicon mold used for the stamping process was prepared by using a crystallographic wet etching method with 45% KOH solution at 80°C. The flexible THz absorber, consisting of micropyramids with a base width of 240 μm, demonstrated nearly perfect absorbance higher than 99% owing to the dramatically reduced surface reflectance of the SRS. The reflectance of the PDMS with the SRS was less than 1%, which is only 1/100th of that measured from a bare PDMS at frequency higher than 1 THz.











... of 240 μm. The reflectance and transmittance of the fabricated flexible PDMS-based SRS samples were measured with a terahertz time-domain spectroscopy (THz-TDS) system (TPS spectra 3000, TeraView). The THz-TDS ...


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