Mitrofanov Oleg, Harrington James A
Department of Electronic and Electrical Engineering, University College London, Torrington Place WC1E 7JE, UK.
Opt Express. 2010 Feb 1;18(3):1898-903. doi: 10.1364/OE.18.001898.
Thin dielectric layers deposited on the inner surface of hollow cylindrical metallic waveguides for Terahertz (THz) waves reduce transmission losses below 1 dB/m. Impact of the dielectric layer on the waveguide dispersion is experimentally investigated by near-field mapping of guided short THz pulses at the input and the output of the waveguide. We obtain dispersion characteristics for the low-loss waveguide modes, the linearly-polarized HE(11) mode and the TE(01) mode, and compare the experimental results to the metallic waveguide dispersion. The additional dispersion due to the dielectric layer is found to be small for the HE(11) mode and the phase velocity is primarily determined by the waveguide radius.
沉积在空心圆柱形金属太赫兹（THz）波导内表面的薄介电层可将传输损耗降低至1 dB/m以下。通过对波导输入和输出端的短太赫兹脉冲进行近场映射，实验研究了介电层对波导色散的影响。我们获得了低损耗波导模式、线偏振HE(11)模式和TE(01)模式的色散特性，并将实验结果与金属波导色散进行了比较。结果发现，对于HE(11)模式，介电层引起的附加色散很小，相速度主要由波导半径决定。
