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Recently, two-dimensional terahertz spectroscopy (2DTS) has attracted increasing attention for studying complex solids. A number of recent studies have applied 2DTS either with long pulses or away from any material resonances, situations that yield unconventional 2DTS spectra that are often difficult to interpret. Here, we clarify the generic origins of observed spectral features by examining 2DTS spectra of ZnTe, a model system with a featureless optical susceptibility at low terahertz frequencies. These results also reveal possible artifacts that may arise from electro-optic sampling in collinear 2DTS experiments, including the observation of spurious rectified or second harmonic signals.
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http://dx.doi.org/10.1364/OE.529152 | DOI Listing |
Compr Rev Food Sci Food Saf
September 2025
Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu, China.
Fruit and fruit-based products are a valuable source of essential nutrients, critical for food security, and drive economic productivity with minimal inputs. The significant rise in global demand for high-quality imported fruit and fruit-based products reflects a shift in consumer awareness and interest in the products origin and potential health-promoting bioactive compounds. Analytical techniques such as liquid chromatography, gas chromatography, inductively coupled plasma techniques, isotope-ratio mass spectrometry (IRMS), near infrared (NIR) spectroscopy, visible near infrared (VIS-NIR) spectroscopy, hyperspectral imaging (HSI), mid-infrared (MIR) spectroscopy, Raman spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, fluorescence spectroscopy, terahertz spectroscopy, dielectric spectroscopy, electronic nose (e-nose), and electronic tongue (e-tongue) coupled with supervised and unsupervised chemometrics can be employed for traceability, authentication, and bioactive profiling of fruit and fruit-based products.
View Article and Find Full Text PDFNano Lett
September 2025
Department of Physics, The University of Tokyo, Hongo, Tokyo 113-0033, Japan.
On-chip terahertz (THz) spectroscopy has attracted growing attention because of its capability of measuring samples far smaller than the Rayleigh diffraction limit. The technique also allows the investigation of nonlinear responses of materials, which is indispensable for the development of ultrafast devices operating with a THz bandwidth. Here, we report the development of an on-chip THz-pump THz-probe spectroscopy technique that enables the study of ultrafast electrical-pulse-induced nonequilibrium phenomena.
View Article and Find Full Text PDFMol Pharm
September 2025
Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, U.K.
The presence of water significantly impacts the physical stability of amorphous solid dispersions (ASDs) by altering polymer molecular mobility. This study investigates the influence of low levels of absorbed water on the molecular dynamics and glass transition behavior of amorphous poly(vinylpyrrolidone--vinyl acetate) (PVP/VA). Melt-quenched PVP/VA discs were conditioned at controlled relative humidities (RH 8.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea.
The thermodynamic equilibrium assumption often invoked in modeling ion migration in solid-state materials remains insufficient to capture the true migration behavior of Li ions, particularly in less-crystalline superionic conductors that exhibit anomalously high Li ion conductivity. Such materials challenge classical frameworks and necessitate a lattice dynamics-based perspective that explicitly accounts for nonequilibrium phonon interactions and transient structural responses. Here, we uncover a phonon-governed Li ion migration mechanism in garnet-structured superionic conductors by comparing Ta-doped LiLaZrTaO (LLZTO4) to its undoped analogue, LiLaZrAlO (LLZO).
View Article and Find Full Text PDFJ Colloid Interface Sci
August 2025
Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China; Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, School of Optical-Electrical and Computer Engin
Precise engineering of hydrophobic microenvironments in synthetic peptide-catecholamine co-assemblies remains challenging for tunable fluorescence. Hierarchical nanostructures were constructed through sequence-specific peptide encoding (GYK tripeptide and Ac-IIIGYK-NH₂ hexapeptide) and co-assembly with catecholamines of graded hydrophobicity. Structural dynamics were analyzed via molecular simulations, HPLC, AFM, and spectroscopy.
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