Characterization of Thin Film Materials Using Near Field THz Imaging

We demonstrate a new technique for characterizing thin film electro-optic (EO) materials. This method is based on resolving the electric field distributions in the near-field region of a split ring resonator (SRR) designed for the terahertz (THz) frequency range. Our simulations are supported experimentally by THz near-field imaging of SRRs directly patterned in contact with a thin-film lithium niobate (LN) crystal as a sensor. Furthermore, we analytically present the effect of the various polarization of applied electric field and calculate the sensitivity of the sensor through different probe beam polarizations.