Terahertz Time-Domain Spectroscopy

Terahertz Time-domain Spectra of Aromatic Carboxylic Acids Incorporated in Nano-sized Pores of Mesoporous Silicate

“…Over recent years terahertz time-domain spectroscopy (THz-TDS) has been demonstrated to be a powerful analytical tool to study low frequency vibrational modes and weak molecular interactions such as hydrogen bonds in the 0.1 -3.0 THz (3 -100 cm -1 ) region, corresponding to the lower end of the far-infrared (FIR) region. 8,9 Coherent detection by switching a photoconductive antenna with femtosecond pulses gives THz-TDS a higher signal-to-noise ratio than FIR spectroscopy, which employs blackbody radiation and thermal detectors.…”

Analytical Terahertz Spectroscopy

“…Other methods such as reflection, attenuated-total reflection (ATR), and ellipsometry are also available, and their principles have been described in detail elsewhere. 23 Since the THz frequency matches the low-frequency vibration and the vibration modes of weak interactions, such as hydrogen bonds, THz-TDS constitutes a unique tool for studying various molecules and materials whose molecular and/or crystal structures are stabilized by these weak interactions. The steric structures of many biological molecules are stabilized by hydrogen bonds, and THz-TDS studies have been undertaken on proteins, 26 polypeptides, 7,27,28 and DNA.…”

“…32 THz-TDS employs several types of optical arrangement classified as transmission, reflection, ATR, and polarization arrangements including ellipsometry. The principles have been detailed elsewhere 23 and here we provide example applications of these methods. It is difficult to observe optically thick samples or samples in polar solvent with transmission THz-TDS owing to the high absorption of THz waves, however, THz-ATR spectroscopy can offer an alternative to transmission THz-TDS.…”

Classification of terahertz spectrometer for transmittance measurements of refractive materials

“…Applications in the terahertz (THz) range whose frequency is approximately from 0.1 to 3 THz have become increasingly common [1,2] since the development of THz time-domain spectroscopy (TDS) [3] in the 1980s. As a result, quantitative TDS measurements are required more than ever before.…”