Design and Fabrication of Substrate-Free Au/SiN_x/Au Metafilm for THz Sensing Application

Abstract

A method of designing and fabricating substrate-free Au/SiNx/Au metafilms as the terahertz (THz) absorber of metamaterial focal plane arrays (MFPA) is reported. The absorption was investigated by the finite integration method simulation and new explicit functions. The substrate-free structure was well fabricated by microelectromechanical system (MEMS) technology. The frequency-dependent absorption of MFPA was measured by THz time-domain spectroscopy (THz-TDS) system. It exhibits an extremely high absorptance of 98.7% at 1.36 THz. The absorption characteristic shows an asymmetric profile, which is well fitted with an Asymmetric Double Sigmoidal (Asym2sig) model. Our results show that the Au/SiNx/Au metafilms have potential in optical readout THz real-time imaging, and highly sensitive sensing applications.

Keywords

• $_{x}$ /Au metafilm%22%2C%22default_operator%22%3A%22AND%22%7D%7D%7D"> Au/SiN<named-content xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" content-type="math" xlink:type="simple"> <inline-formula> <tex-math notation="LaTeX">$_{x}$</tex-math> </inline-formula> </named-content>/Au metafilm
• substrate-free
• asymmetric peak model
• THz sensing