Investigation of ITO Films in the THz Range: Optical Properties and Interaction with Intense Radiation

The interaction of the radiation of the THz spectral range with indium tin oxide (ITO) films with a thickness of less than 300 nm on fused quartz substrates has been investigated. The dependence of their complex refraction index within the range 0.2–1.2 THz on their thickness has been determined. The properties of the films in this range are well described by the Drude model, whose parameters are determined from approximation of data in a wide spectral range. The model demonstrates a linear increase in the specific conductance with growing thickness and can be useful to calculate antireflection coatings for the radiation of the THz spectral range. The results of the investigation of the interaction of intensive THz radiation with the peak and medium intensity of up to 2 MW/cm $${}^{2}$$ and 1.2 kW/cm $${}^{2}$$ , respectively, have shown the absence of laser damage to the films and have made it possible to outline the scope of application of ITO films as dichroic mirrors of the transport channels of intensive THz beams.