ИСТИНА

We have demonstrated a purely dielectric, flexible, single mode, narrowband waveguide for the 3 THz frequency. In comparison with the previously known studies of TLF we increased the used frequency from 0.3-1.5 THz to 3 THz, decreased the transversal TLF size from 1 cm to 3 mm. For filtering out undesirable frequencies of THz QCL radiation and selecting desired QCL frequency a set of waveguides can be used due to a steep slope of their transparency window. At the same time, the key application of the TLF seems to be a way to deliver single mode THz radiation to hardly accessible areas. A good agreement of the experimental data and theoretical calculations allows accounting for the existing technical limitations.