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THz transmission spectra of the commonly used pain killers-aspirin and paracetamol were measured using the FTIR technique and calculated using the density functional theory method. Despite the shift in the frequencies, there are common absorption bands between these compounds. The common bands were established to be primarily due to the various movements of the benzene ring.
This review aims to bring together information about the development of radiation sources and the most striking examples of using of gyrotrons for spectroscopy and diagnostics of various media. It describes the main features of terahertz gyrotrons. It provides the most striking examples of modern CW and pulse gyrotrons working in the specified frequency range, highlights a number of topical applications...
The origin of fast relaxation water in the terahertz frequency range have been elusive for years. In this contribution we have experimentally investigated the change in dynamical structure of water in salt solution using broadband dielectric relaxation spectroscopy (DRS) in the GHz to THz region to study the fast water. Numerical simulations have been conducted to quantify the dynamical properties...
Strong light-matter interaction leads to the appearance of new states, i.e. exciton-polaritons, with photophysical properties rather distinct from their constituents. Recent developments in fabrication techniques allow us to make metallic structures with strong electric field confinement in nanoscale mode volumes, allowing for a facile assembly of strongly coupled systems at room temperature based...
The ability to distinguish between different states of a given cell, as well as between different types of cells, is crucial for a variety of fundamental and clinical life sciences applications. Those include the monitoring of biochemical processes in a living cell and effective early cancer screening, to name just a few. The most common approach to differentiating between different cell types is...
Interactions between conjugated polyenes and light play important role in photosynthesis and vision. To understand and to manipulate the conversion of light energy to chemical energy in conjugated polyenes, we investigated the relaxation processes in the simplest conjugated diene, 1, 3-butadiene (BD) shown in Fig. 1, by time-resolved photoelectron spectroscopy using high harmonics (TRPES) [1]. In...
High-harmonic generation (HHG) is a nonlinear process that converts intense infrared (IR) radiation into high-frequency light [1, 2]. It can be understood as a sequence of three steps: (1) tunnel ionization of an atom or a molecule induced by the strong IR field, (2) laser-driven acceleration of the electron in the continuum, and (3) recombination with the parent ion resulting in the emission of harmonic...
Microcalcifications are the unique early marker of breast cancer. However, the relationship between their occurrence and malignancy is still unknown. Vibrational spectroscopy techniques are label-free and chemically specific. They have been used to characterize these calcifications based on their composition, e.g. content of carbonates, phosphates and proteins. The first step of the study was to characterise...
Absorption spectroscopy is attractive for combustion diagnostics because it allows in-situ and calibration-free quantification of reactants/products and thermometry. However, spectra measured at atmospheric pressure in the near-infrared telecom range, where laser sources and optical components are readily available, suffer from strong water interference. Cavity-enhanced optical frequency comb spectroscopy...
The advent of attosecond spectroscopy, in particular high harmonic generation spectroscopy, has led to advances in following electronic dynamics in atoms and molecules on their natural timescale. The recent discovery of the high harmonic generation in bulk solids [1-8] has opened the door for applying HHG spectroscopy for ultrafast investigations of the electronic dynamics in the condensed phase,...
The analysis of spectra is fundamental to our modern understanding of wave optics and color perception. Every student should have the opportunity to conduct their own optical emissions experiments. Since spectrometers are expensive and accurate calibration is necessary to achieve high quality spectra, we developed a remote lab for optical spectrometry. The VirtualRemoteLab combines the remote lab...
This work develops a simple technique to evaluate the sirloin pork quality based on its electrical impedance. The measurement of tissue electrical properties can reveal the quality of meat because tissue has certain electrical characteristics such as impedance and conductivity, which change according to post-mortem time. The preliminary results show that the impedance of pork is reduced by time and...
In this work the experimental results are presented showing the spectroscopic performance of the ASIC multichannel charge-sensitive preamplifier of TRACE (TRacking Array for light Charged particle Ejectiles). The results were obtained connecting a silicon pad detector to a custom-designed preamplifier board with eight ASIC CSPs. The detector and the board were put in a vacuum chamber with a triple...
We demonstrate a mode-locked interband cascade semiconductor laser operating in the 3 μm wavelength range. Such broadband optical sources are relevant for spectroscopic applications in the mid infrared range where the fundamental rotational-vibrational bands of most light molecules are found.
In this newly reported discovery, common THz absorption signatures from lactose and biotin are found to significantly “red-shift” in frequency with increase in hydration, especially in the hydration range of ∼10 to 20% by weight. Interestingly, the associated linewidth (i.e., FWHM) sometimes broadens (consistent with the Lorentzian oscillator model) as in biotin, but other times narrows somewhat,...
Tuning the band structure of a topological insulator is of interest for developing electronic devices or superconducting devices. Here we report the strain-dependent results for Bi2Se3 films of various thicknesses that are grown via a self-organized ordering process. From the UV photoemission/inverse photoemission spectroscopy (UPS/IPES) results, ab initio calculations and THz-TDS data, significant...
We performed spectroscopic studies of water-containing beryl crystals. At terahertz frequencies, we observed a strongly temperature-dependent spectral feature, corresponding to a collective excitation caused by dipole-dipole interactions between separate H2O molecules. We associate the excitation with a soft mode signaling an incipient ferroelectric state within the water molecular subsystem. Single-particle...
In the present paper a preliminary design and implementation of a readout interface for strip detectors, using Applied Specific Integrated Circuits (ASICs) is discussed. Key issues are the parameters and features of the main constituent parts of the system: strip detectors, ASICs and driving electronics, as well as the preliminary test-results. The readout interface is intended to be used as a means...
Charged water interfaces are ubiquitous and responsible for many important processes in nature and modern technologies, such as protein folding, electrochemistry, and photocatalysis. They appear in the form of an electric double layer that can be divided into two sub-layers. One is the so-called Stern layer composed of one to two hardly mobile, hydrogen-bonded, water monolayers next to the charged...
There has been a recent growth of activity in nonlinear time domain terahertz spectroscopy because of the development of a number of intense lab based sources and ultra-broadband detection schemes. Much of the interest stems from the possibility of exploring new physics by driving condensed matter far from equilibrium with THz fields in the 0.1 to 10MV/cm range [1]. The variety of different approaches...
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