22 October 2013 Metal-organic hybrid resonant terahertz absorbers with SU-8 photoresist dielectric layer
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We report on the characterization of metal-organic hybrid metamaterials for MEMS-based terahertz (THz) thermal sensors and on the characterization of refractive index of SU-8 in the THz band. This type of metamaterial, coupled with the applicability of SU-8 as a structural material, offers possibilities for quick, simple microfabrication of THz imagers. SU-8, a negative photoresist, is a low-cost material that can quickly be spun onto a substrate at a wide range of thicknesses, and then photolithographically patterned into a variety of structures. It is also transparent to THz radiation and thus a suitable choice for a dielectric spacer in metamaterials. We investigated metamaterials consisting of a 0.18 μm Al ground plane and 0.18-μm layer of patterned Al separated by a dielectric spacer of ∼0.5  μm of SU-8. Absorption close to 70% at around 6.1 THz was observed. A model was developed to simulate absorption spectra of several metamaterials, agreeing well with experiments. Matching simulation to measurements was used to determine the refractive index of SU-8 at THz frequencies, extending the known values from 0.1 to 1.6 THz to as far as 10 THz. Finally, Kirchoff’s law for these metamaterials was verified and their use as THz emitters demonstrated with about 0.8  mW/cm 2 output.
© 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)
Dragoslav Grbovic, Dragoslav Grbovic, Fabio Alves, Fabio Alves, Brian T. Kearney, Brian T. Kearney, Benjamin Waxer, Benjamin Waxer, Rolando Perez, Rolando Perez, George Omictin, George Omictin, } "Metal-organic hybrid resonant terahertz absorbers with SU-8 photoresist dielectric layer," Journal of Micro/Nanolithography, MEMS, and MOEMS 12(4), 041204 (22 October 2013). https://doi.org/10.1117/1.JMM.12.4.041204 . Submission:

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