Ultrafast Frequency-Shift Dynamics at Temporal Boundary Induced by Structural-Dispersion Switching of Waveguides

We experimentally demonstrate the observation of a frequency-shift dynamics at a temporal boundary in the terahertz (THz) region relying on a scheme that controls the structural dispersion of a metal-semiconductor waveguide. Ultrafast structural-dispersion switching is achieved within a subpicosecond timescale by illuminating a waveguide surface with an optical pump pulse during the propagation of a THz pulse in the waveguide. Owing to the relatively high conversion efficiency, up to 23%, under the condition that the frequency shift is sufficiently larger than the bandwidth of the incident pulse, the rapid variation of the THz frequency around the temporal boundary is directly observed in the time domain.

Automated summary

The experimental demonstration involves observing frequency-shift dynamics at a temporal boundary in the terahertz (THz) region using a scheme that controls the structural dispersion of a metal-semiconductor waveguide. Ultrafast structural-dispersion switching is achieved within a subpicosecond timescale by illuminating the waveguide surface with an optical pump pulse during THz pulse propagation. The high conversion efficiency, up to 23%, allows for direct observation of rapid THz frequency variation around the temporal boundary.