Time‐Domain Integration of Broadband Terahertz Pulses in a Tapered Two‐Wire Waveguide

Abstract

In this work, the time‐domain integration of broadband terahertz (THz) pulses via a tapered two‐wire waveguide (TTWWG) is reported. Such a guiding structure consists of two metallic wires separated by a variable air gap that shrinks down to a subwavelength size as the movement takes from the waveguide input to its output. It is shown that while an input THz pulse propagates toward the subwavelength output gap, it is reshaped into its first‐order time integral waveform. In order to prove the TTWWG time integration functionality, the THz pulse is detected directly within the output gap of the waveguide, so as to prevent the outcoupling diffraction from altering the shape of the time‐integrated THz transient. Since the time‐domain integration is due to the tight geometrical confinement of the THz radiation in a subwavelength gap volume, the TTWWG operational spectral range can easily be tuned by judiciously changing both the output gap size and the tapering angle. The results lead to the physical realization of a broadband, analog THz time integrator device, which is envisioned to serve as a key building block for the implementation of complex and ultrahigh‐speed analog signal processing operations in THz communication systems.

Terahertz Resonances of Transverse Standing Waves in a Corrugated Plate Waveguide

“…Among them, the THz waveguide transmission technology with low loss, long distance, and low dispersion is very essential due to the signal distortion in free space, the attenuation caused by atmospheric scattering, and the water vapor absorption. Various THz waveguides have been proposed and investigated, such as hollow metallic structures [20], metal wires [21], dielectric waveguides [22], parallel plate structures [23], photonic crystal fibers [24], [25], rectangular structures [26], plasmonic [27], and tapered waveguide [28]. However, most of researchers focused on the low loss and low dispersion THz waveguides and paid little attention to the transverse standing waves (i.e., the guided wave modes).…”

Low Loss THz Waveguides and Its Potentials towards 6G Communication: A Brief Chronicle Review

“…Bare metallic wire THz waveguides are popular due to their different advantages such as low loss and low dispersions and ability of radiation manipulation and processing such as [31,32].…”

Versatile metal-wire waveguides for broadband terahertz signal processing and multiplexing

“…The concept of engraving grooves with multiscale structures, combining the merits of photonic crystals and metamaterials, offers additional degrees of freedom to tailor the spectral response of the entire structures. This paves the way for the realization of versatile signal-processing functionalities, including custom-engineered filtering 29 , time differentiation and integration 30 , as well as modulation/demodulation. In parallel, we have experimentally demonstrated the FWWG topology, which provides two independent fundamental modes with orthogonal polarization states for the low-loss and nearly dispersion-free propagation of polarization-division multiplexed THz pulses.…”