Terahertz time-domain transmission and reflection spectroscopy of niobium

Abstract

We have developed a terahertz time-domain spectroscopy (THz-TDS) system for transmission and reflection measurements of metallic thin films. Using our THz-TDS system, we studied the conventional superconductor niobium (Nb) in the normal state in the spectral range from 5 to 50 cm-1. Both the real and imaginary parts of the conductivity are acquired without Kramers-Kronig analysis. Nb exhibits a nearly frequency independent real conductivity spectrum in the terahertz range, with a very small imaginary part.

Discrimination of Cynanchum wilfordii and Cynanchum auriculatum by terahertz spectroscopic analysis

“…The THz‐TDS has the advantage of being capable of simultaneously measuring the amplitude and phase of the electric field from the characteristics of the light source generating the terahertz wave. Therefore, complex dielectric constants can be calculated without using the Kramers–Kronig relationship, high signal‐to‐noise ratios (SNRs) can be obtained, and pulses originated from multiple reflection can be separated according to time …”

“…Therefore, complex dielectric constants can be calculated without using the Kramers-Kronig relationship, high signal-to-noise ratios (SNRs) can be obtained, and pulses originated from multiple reflection can be separated according to time. 11 In this study, we present scientific evidence for the discrimination of two similar Cynancum species by using THz-TDS to investigate the difference of signal values between the two herbs.…”