Linearity evaluation of a THz-TDS system by a step attenuator using metalized films

We have experimentally developed a terahertz wave step attenuator (TSA) to evaluate linearity of a terahertz time-domain spectroscopy (THz-TDS) system. The TSA is constructed by stacking metalized-film attenuators (MFAs) which have different transmittance. Sputter deposition of Inconel
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alloy on thin polyester films is used to fabricate the MFAs. Good repeatability and flatness of the TSA are confirmed in a transmission measurement by the THz-TDS system. This paper reports on linearity evaluation of the THz-TDS system by using the TSA.