T-Ray Sensing and Imaging

Abstract

An Australian research group has investigated a number of terahertz application areas including liquid Tray spectroscopy, bioaffinity sensing, image rendering, tomography, microwire Tray transmission, and detection through plastic layers.

Material thickness optimization for transmission-mode terahertz time-domain spectroscopy

“…The absorption coefficient increases quadratically, also in accordance with [24]. Note that small shifts in the refractive indices of plastics at T-ray frequencies are known to be caused by slight hygroscopicity [11] and differences in the manufacturing process. The optimum thickness for PVC, which supposedly yields the lowest variance in the measured optical constants, is determined from the absorption coefficient using the proposed model in Eq.…”

“…The optimum thickness for THz-TDS measurement is determined using Eq. (11). The absorption coefficients, measured at room temperature, are taken from various sources: water [20]; PMMA, TPX [21]; HDPE [22].…”

“…The optimum thickness for PVC, which supposedly yields the lowest variance in the measured optical constants, is determined from the absorption coefficient using the proposed model in Eq. (11). However, the measured absorption coefficient contains error from noise, watervapor absorption, and Fabry-Pérot fringes.…”

“…A major contribution to the uncertainty in the measured optical constants is from the fluctuations and noise in the measured signals [11], which are mainly due to electronic [12], optical [13], and mechanical [14] components. Thus, in order to reduce the uncertainty in optical constants, one may attempt to tackle the noise in the signals directly.…”

Porous fibers: a novel approach to low loss THz waveguides

“…The frequency range is loosely defined as 0.1-10 THz [1]. Terahertz spectroscopic techniques have many applications, as for example in detection of biological and chemical materials [2,3]. Many of these preliminary proof-of-principle studies have been carried out in spectroscopy systems, where terahertz radiation propagates in free space.…”