Frequency-dependent characterization of THz Sommerfeld wave propagation on single-wires

Abstract

In this work, measurements and numerical field simulations highlighting the characteristic propagation behavior of THz surface-wave pulses along bare and dielectrically coated metal wires are presented. An optoelectronic time-domain measurement setup with a freely-positionable probe-tip is used for detection of electrical field transients after different propagation lengths along the wires. Frequency-dependent attenuation and dispersion parameters are determined in the range of 0.02 THz to 0.4 THz. Our results are in good agreement with numerical field simulations considering the propagation of an axial Sommerfeld surface-wave with metallic and dielectric losses. We discuss the influence of wire radius on wave propagation behavior and the application of THz single-wires for sensing.

Review of Near-Field Terahertz Measurement Methods and Their Applications

“…These waves are extensively used in THz near-field imaging as shown in Section 2.6. The Aachen group directly studied the field at the wire itself using their PC probe-tip based setup [100] which leads to use tapered wire as near-field probe [10]. The Mittleman group has measured the spatial profile of the electric near-field at the end of a wire where THz waves were propagating.…”

Frequency-dependent radiation patterns emitted by THz plasmons on finite length cylindrical metal wires

“…The THz pulses propagate on these wires as surface plasmon polaritons having a radial polarization and are often referred to as Sommerfeld waves [3,4]. It has been shown that these pulses can travel relatively long distances of up to a few meters on these wires, since they experience little attenuation [2,3].…”

Coherent and ultrafast optoelectronics in III–V semiconductor compounds

“…Frequency-domain propagation parameters (not shown here) of the wire have been retrieved from the time-domain data by a procedure described in [55]. Using these freely-positionable PC probetips the frequency-dependent attenuation and dispersion behaviour of Sommerfeld wires was measured in qualitative and quantitative agreement with numerical field simulations [64]. Compared to other approaches, where the field radiated from the end of the waveguide is probed, our method appears to be favorable for waveguide characterization since the field pattern radiated from an open end of a waveguide is highly-frequency dependent [65].…”

“…The probe-tip has been applied to characterize the propagation properties of THz Sommerfeld wire waveguides by recording the amplitude and phase information of transient electric fields after different propagation distances [64]. For this task, a radial LT-GaAs-based PC antenna, as sketched in Fig.…”