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Terahertz time domain spectroscopy has been done for reverse micellar solution in the temperature range from ∼190 K to room temperature. The temperature dependence of the absorption lineshape demonstrates that dynamics of water in a nanometer-sized droplet change at low temperatures, which will be ascribed to water shedding from reverse micelles.
This study focuses on the seals of validation, sealing written documents, used in the Western Middle Ages, especially wax seals. We use THz spectroscopy and imaging for non-destructive evaluation of natural materials within those seals. Using a time domain THz spectroscopy and imaging system, THz transmission images are generated in the 0.1–3 THz range and demonstrate that the spectral properties...
Transmission spectra of wet human teeth and dentin slices, together with blood of different flow rates were investigated over a wide spectral range, from visible to terahertz (THz) light. The results make it possible to find the optimum light frequency for an all-optical determination of pulpal blood flow and, consequently, for clinically diagnosis of tooth vitality.
Terahertz (THz) reflection spectroscopy has the potential to extract unique spectral signatures from various materials of interest, but these signatures can be distorted by rough surface scattering, low signal strength, and alignment errors. One method of addressing these challenges and increasing gain is to coherently combine information across frequency bands. This method, called correlation processing,...
We have investigated the THz superfocusing effect using a metal tapered parallel waveguide and THz dielectric response of plastic tubes sandwiched between parallel plates of the waveguide. We observed that about 20% amplitude of terahertz wave can be transmitted through a 20-µm slit of the waveguide.
Concerning several attacks using letter bombs within Europe in the last couple of years and the highly rising number of new drugs, there is a need for new kinds of detection devices for explosives and drugs. We present a postscanner on basis of Terahertz (THz) spectroscopy using novel chemometric methods for the evaluation of detected THz fingerprints.
In this paper we will discuss ZnO nanotube formation by chemical wet etching of ZnO nanorod. Photoluminescence measurements and Terahertz time-domain spectroscopy (THz-TDS) [1] are conducted to study its variation of optical properties. The mechanism of nanotube formation is characterized and optical properties are compared between nanorods and nanotubes.
Tuberculosis (TB) is a tropical disease affecting millions of lives. Conventional chemical based methods such as acid-fast technique for the detection of TB are time consuming and suffer from low sensitivity and specificity. We present a non-invasive detection technique for TB using IR and NIR spectroscopy. Spectral fingerprints of Mycobacterium are compared with E-Coli, Smegmatis and BCG bacteria...
Measurement and Monte-Carlo simulations of THz photoconductivity spectra of CdS nanocrystalline films revealed a strong coupling between adjacent nanocrystals. Investigation of ultrafast dynamics provides information about initial sub-picosecond carrier cooling and subsequent carrier recombination.
In this paper, we explore the use of reverse micelle systems to investigate the terahertz absorption of varying water trehalose solutions. Fourier Transform Infra-Red (FTIR) spectroscopy and molecular dynamic simulations were used to determine the absorption at each concentration. Both sets of results showed increasingly sterically hindered waters with increasing trehalose concentration.
The quality of glued joints in nonmetallic samples was evaluated using a standard THz-TDS system in the transmission configuration. Our results show that THz waves can indeed become a powerful tool for NDE of nonmetallic industrial equipment.
The electron has been investigated thoroughly and applied widely since it was discovered by J. J. Thomson in 18971. The motion of electrons as well as their manipulation and control, especially in semiconductors, have been fundamental problems in all modern scientific and technologic endeavor. In early stages of modern physics and electronics, classical and linear motions of electrons in vacuum under...
Chemical vapour deposition (CVD) grown graphene sheets were investigated using optical-pump terahertz-probe spectroscopy, revealing a dramatic variation in the photoinduced terahertz conductivity of graphene in different atmospheres.
We carried out terahertz-time domain spectroscopy of a chemical vapor deposition (CVD) diamond substrate and derived its complex permittivity from 0.3 to 2.2 THz. The permittivity in this region shows broad band features. It is suggested that some other dielectric response is present above 2.2 THz in the CVD diamond.
In this paper, an application of terahertz time-domain spectroscopy (THz-TDS) to detection of food contaminants is introduced. Spectra of chemical food contaminants, carbendazim, chlorothalonil, and isoprothiolane were measured and analyzed by THz-TDS in frequency from 0.2 – 3.5 THz.
We report on the development and testing of fiber-coupled, LT-GaAs photomixers operating at cryogenic temperatures which are designed for variable temperature terahertz spectroscopy of chemical, electronic and magnetic materials.
Hydration state of lipid bilayer during the gel to fluid phase transition is measured with THz time domain spectroscopy (TDS). Hydration water showed bulk-water-like behavior at gel phase, but showed non-bulk-like behavior at fluid phase.
In this work we present mid-infrared (114 meV–224 meV) polarization-sensitive measurements on multilayer epitaxial graphene, which reveal graphene's rich and complex cyclotron resonant (CR) structure. By using Fourier transform Kerr spectroscopy we are able to separate and identify cyclotron resonances from graphene multilayers with various stacking orders and thicknesses. Moreover, from the identification...
Terahertz (THz) spectroscopy and imaging techniques have great potential as analytical tools in the field of heritage science. The advantages of THz technology, such as nondestructive spectroscopic imaging and tomography, are introduced including case studies of historic masterpieces.
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