Time-resolved imaging of mode-conversion process of terahertz transients in subwavelength waveguides


We studied the mode-conversion process of terahertz pulses from a planar subwavelength waveguide to a tilted rectangular subwavelength waveguide. An unusual wavefront rotation, which led to an extra conversion time, was observed using a time-resolved imaging technique. We simulated the mode conversion process by a finite-difference time-domain method, and the results agreed well with the experiments. According to the simulations, the conversion time was demonstrated to become longer as the tilt angle or width of the rectangular waveguide increased. This work provides the possibility to optimize the future high-speed communications and terahertz integrated platforms.

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This work was supported by the National Natural Science Foundation of China (NSFC) (Grant Nos. 61705013 and 61378018), the 111 Project (No. B07013), and the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT 13R29).

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Correspondence to Qiang Wu or Bin Zhang.

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Lu, Y., Wu, Q., Zhang, Q. et al. Time-resolved imaging of mode-conversion process of terahertz transients in subwavelength waveguides. Front. Phys. 14, 42502 (2019). https://doi.org/10.1007/s11467-019-0892-5

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  • ultrafast phenomenon
  • mode conversion
  • subwavelength waveguides
  • terahertz waves