Optical Properties and Crystallization of Natural Waxes at Several Annealing Temperatures: a Terahertz Time-Domain Spectroscopy Study

Tian, Lu; Xu, Xinlong

doi:10.1007/s10762-017-0461-3

Cited by 13 publications

(7 citation statements)

References 35 publications

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“…We notice that the tissue edges are well resolved, especially in the y -scan, when n drops sharply at a narrow paraffin region between two tissue nodules [see also Figure (a)]. The THz refractive index of the paraffin found by the MAP technique closely matches the literature value . The values of n and α changing within the tissue regions can help unveil changes in the tissue microenvironment, such as normal/tumor tissue boundaries, by tracing the corresponding values.…”

Section: Resultssupporting

confidence: 70%

“…The THz refractive index of the paraffin found by the MAP technique closely matches the literature value. 31 The values of n and α changing within the tissue regions can help unveil changes in the tissue microenvironment, such as normal/tumor tissue boundaries, by tracing the corresponding values. Finally, at intersection points between the x - and y -scans, indicated by arrows in both Figure 6 (b) and (c), the values of n and α, respectively, match precisely with each other.…”

Section: Resultsmentioning

confidence: 99%

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Development of Terahertz Imaging Markers for Pancreatic Ductal Adenocarcinoma using Maximum A Posteriori Probability (MAP) Estimation

et al. 2023

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Pancreatic ductal adenocarcinoma (PDAC) is one of the significant reasons for cancer-related death in the United States due to a lack of timely prognosis and the poor efficacy of the standard treatment protocol. Immunotherapy-based neoadjuvant therapy, such as stereotactic body radiotherapy (SBRT), has shown promising results compared to conventional radiotherapy in strengthening the antitumor response in PDAC. To probe and quantify the antitumor response with SBRT, we propose to study the tumor microenvironment using terahertz time-domain spectroscopy (THz-TDS). Since the tumor's complex microenvironment plays a key role in disease progression and treatment supervision, THz-TDS can be a revolutionary tool to help in treatment planning by probing the changes in the tissue microenvironment. This paper presents THz-TDS of paraffin-embedded PDAC samples utilizing a clinically relevant genetically engineered mouse model. This Article aims to develop and validate a novel timedomain approximation method based on maximum a posteriori probability (MAP) estimation to extract terahertz parameters, namely, the refractive index and the absorption coefficient, from THz-TDS. Unlike the standard frequency-domain (FD) analysis, the parameters extracted from MAP construct better-conserved tissue parameters estimates, since the FD optimization often incorporates errors due to numerical instabilities during phase unwrapping, especially when propagating in lossy media. The THzrange index of refraction extracted from MAP and absorption coefficient parameters report a statistically significant distinction between PDAC tissue regions and their healthy equivalents. The coefficient of variation of the refractive index extracted by MAP is one order of magnitude lower compared to the one extracted from FD analysis. The index of refraction and absorption coefficient extracted from the MAP are suggested as the best imaging markers to reconstruct THz images of biological tissues to reflect their physical properties accurately and reproducibly. The obtained THz scans were validated using standard histopathology.

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Section: Resultssupporting

confidence: 70%

Section: Resultsmentioning

confidence: 99%

Development of Terahertz Imaging Markers for Pancreatic Ductal Adenocarcinoma using Maximum A Posteriori Probability (MAP) Estimation

et al. 2023

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“…The vibrational modes of C5H12-C10H22 are composed of three types in the 0.2-5.5 THz region, namely, skeleton vibration of carbon-carbon (C-C) chain in the yoz plane, swing vibration of C-C chain in the xoy plane, and torsional vibration of methyl group along the y axis [13]. Previously, the absorption peak at 2.2 THz has been obtained in the THz-TDS of n-paraffin crystals (C19H40, C27H56, C29H60, C30H62, and C36H74), liquid paraffin, lube base oils, lubricating oils and many other substances [10][11][12][14][15][16]. Thus, based on these literatures, the recorded 2.2 THz assigned to the B1u mode, corresponds to the intermolecular interaction between the parallel alkane molecules [10,17].…”

Section: Resultsmentioning

confidence: 99%

“…Terahertz time-domain spectroscopy (THz-TDS) has recently received great attention with the expectation that it will provide new insights into complex polymer systems (such as order-disorder transition of nonadecane, higher order conformation, assignment of intermolecular vibration modes and structural characterization, characterizing polymorphism and crystal transformation of polylactide, etc. ), and several relevant studies have been reported [10][11][12]. In this paper, the magnetic field dependence of the THz optical properties are experimentally characterized using THz-TDS.…”

Section: Introductionmentioning

confidence: 98%

Magnetic field induced reduction of intermolecular force between the normal alkanes

Tian,

Zhang

2023

TST

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Magnetic field can significantly change the characteristics of alkanes and related petroleum products, and the physical mechanism has received much attention for several years. Terahertz time-domain spectroscopy (THz-TDS) is employed in this paper to characterize the optical parameters and diamagnetic anisotropy properties of liquid normal alkanes (n-alkanes) under the action of a magnetic field. The corresponding absorption coefficients of samples are obtained by a fast Fourier transform, and the orientation characteristics of n-alkanes are analyzed under a relative weak magnetic field. The results indicate THz-TDS has great potential for the identification of intermolecular interaction in the organic molecules.

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“…Due to the rather large beam diameter of 2 inches in the given experiment, it was necessary to choose a different type of sample production, since such large molds were not available. Paraffin wax has proven to be an ideal carrier material, as it shows almost no absorption in the terahertz frequency range and has also a low refractive index 24 of about 1.54. The amount of the additives to the paraffin wax plate ranges between 0.0 g and 2.1 g. Considering the area of the plate of 107x80 mm 2 and assuming a homogeneous distribution, this corresponds to concentrations between 0 mg/mm 2 and 0.25 mg/mm 2 , respectively.…”

Section: Terahertz Spectroscopymentioning

confidence: 99%

Quantum-inspired terahertz spectroscopy with visible photons

Kutas

Haase

Klier

et al. 2021

Optica

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Terahertz spectroscopy allows for identifying different isomers of materials, for drug discrimination as well as for detecting hazardous substances. As many dielectric materials used for packaging are transparent in the terahertz spectral range, substances might even be identified if packaged. Despite these useful applications, terahertz spectroscopy suffers from the still technically demanding detection of terahertz radiation. Thus, either coherent timedomain-spectroscopy schemes employing ultrafast pulsed lasers or continuous-wave detection with photomixers requiring two laser systems are used to circumvent the challenge to detect such low-energetic radiation without using cooled detectors. Here, we report on the first demonstration of terahertz spectroscopy, in which the sample interacts with terahertz idler photons, while only correlated visible signal photons are detected -a concept inspired by quantum optics. To generate these correlated signal-idler photon pairs, a periodically poled lithium niobate crystal and a 660 nm continuous-wave pump source are used. After propagating through a single-crystal nonlinear interferometer, the pump photons are separated from the signal radiation by highly efficient and narrowband volume Bragg gratings. An uncooled scientific CMOS camera detects the frequency-angular spectra of the remaining visible signal and reveals terahertz-spectral information in the Stokes as well as the anti-Stokes part of collinear forward generation. Neither cooled detectors nor expensive pulsed lasers for coherent detection are required. We demonstrate spectroscopy on the well-known absorption features in the terahertz spectral range of -lactose monohydrate and paraaminobenzoic acid by detecting only visible photons.

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Optical Properties and Crystallization of Natural Waxes at Several Annealing Temperatures: a Terahertz Time-Domain Spectroscopy Study

Cited by 13 publications

References 35 publications

Development of Terahertz Imaging Markers for Pancreatic Ductal Adenocarcinoma using Maximum A Posteriori Probability (MAP) Estimation

Development of Terahertz Imaging Markers for Pancreatic Ductal Adenocarcinoma using Maximum A Posteriori Probability (MAP) Estimation

Magnetic field induced reduction of intermolecular force between the normal alkanes

Quantum-inspired terahertz spectroscopy with visible photons

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