Terahertz Sensing of Thin Poly(ethylene Terephthalate) Film Thickness Using a Metallic Mesh

A metallic mesh, i.e., a metallic thin film with regularly spaced openings, works as a band-pass filter in the terahertz region. The filter's transmittance is far higher than the open-area ratio and its transmission spectrum is affected by the index of refraction in and above the openings. Therefore, metallic-mesh films can be used as high-sensitivity sensing or imaging conduits if samples adhere to the metal surface. Here, we report on our success in detecting 1-mu m-thickness differences in poly(ethylene terephthalate) (PET) films and recording two-dimensional (2D) images using metallic-mesh sensing and imaging applications. (C) 2009 The Japan Society of Applied Physics