Enhanced absorption of liquid thin layer on terahertz nanoantennas

Abstract

Absorption of terahertz electromagnetic waves by liquid thin layers on metallic nano-slot antennas is investigated. Nano-slot antennas, metallic film with nanometer-sized slots, are known to show strong resonance at certain frequency, and sensitivity to the dielectric environment. Liquid thin layer is formed using spin-coated PDMS and patterned silicon oxide, which prevent liquids from smearing out. In the presence of liquids the transmission spectra of nano-slot antennas show large amplitude modulations and peak shifts according to the dielectric properties of the liquids. The tendency becomes larger with smaller antenna width. With further optimizations in sealing and antenna structure, this scheme is expected to open up the possibility of measuring much more minute samples, such as a few-layer molecule layer.