Transmission Measurements Research Articles

Harmonic radiation contribution and X-ray transmission at the Small Quantum Systems instrument of European XFEL.

Transmission measurements of the soft X-ray beamline to the Small Quantum Systems (SQS) scientific instrument at the SASE3 undulator of European XFEL are presented. Measurements are reported for a wide range of photon energies (650 eV to 2400 eV), using X-ray gas monitors as well as a bolometric radiometer. The results are in good agreement with simulations for the beam transport and show a transmission of up to 80% over the whole photon energy range. The contribution of second- and third-harmonic radiation of the soft X-ray undulator is determined at selected photon energies by performing transmission measurements using a gas absorber to provide variable attenuation of the incoming photon flux. A comparison of the results with semi-analytic calculations for the generation of free-electron laser pulses in the SASE3 undulator reveals an influence of apertures along the beam transport on the exact harmonic content to be accounted for at the experiment. The second-harmonic content is measured to be in the range of 0.1% to 0.3%, while the third-harmonic contributed a few percent to the SASE3 emission. For experiments at the SQS instrument, these numbers can be reduced through specific selections of the mirror reflection angles.

Fundamental Investigations of Propagation through the Land–Air–Water Interface in a Controlled Littoral Environment

ABSTRACT Interpreting signals from mechanical waves that cross material media boundaries is challenging due to the historical development of instrumentation suitable to study waves in each distinct medium, leading to discrepancies in boundary and adjacent media descriptions and governing physics related to each media. Nowhere is this more significant than in littoral zones at the convergence of land–air–water (LAW) domains. In short, a comprehensive physics framework does not exist that can accurately predict how waveforms freely traverse these media boundaries resulting in a critical fundamental science knowledge gap that can correlate received waveforms to actual source generators. Furthermore, the preponderance of research has treated media boundaries as lossy reflectors rather than poor transmitters, resulting in a rudimentary understanding of wave transformation over subsurface inhomogeneities and boundaries. This article details the experimental component of a new transdisciplinary effort to characterize the full LAW wavefield within a littoral zone to overcome the mixed media challenges. The fusion of disciplines, including air and underwater acoustics, geophysics, and hydrology, aims to develop a full-wavefield description of coupled media in the environment. Beginning with a simplified scenario, the experimental design accommodates for measurements of wave transmission across land–water, air–water, and land–air boundaries in a controlled, constructed, and prototypical littoral zone. This article reviews the test site design, construction, and preliminary experimental results. The challenges of designing and implementing an experiment that explicitly observes signal propagation across the media boundaries without distorting the boundaries and includes sources and sensors in all three environments are discussed.

Negative group-delay assisted anomalous propagation in stacked Split Ring Resonator array

This paper explores a novel method to achieve negative group delay-assisted anomalous propagation without significant signal attenuation using stacked Split-Ring Resonator (SRR) array in the microwave regime. A sub-wavelength stacking thickness between the SRR layers creates transverse magnetic dipole moments due to the excitation of anti-parallel currents on these layers resulting in increased transmission amplitude. Multipole scattering theory has been utilized to extract the reason behind anomalous propagation by evaluating the scattered power from the principal electric and magnetic dipole moments excited on the structure. Time-domain analysis are performed on the samples, and negative group delay behavior is confirmed by observing the precedence of the output electromagnetic Gaussian pulse within the anomalous dispersion regime. The coupling effects are studied numerically using full-wave solvers and verified in experiments by performing transmission measurements inside an anechoic chamber.

Calibrated transmission and reflection from a multi-qubit microwave package.

We report calibrated microwave transmission and reflection measurements of a qubit sample holder at millikelvin temperatures. The methodology we present extends our previous work on one-port cryogenic short-open-load (SOL) calibration to a two-port SOLT measurement by implementing an unknown thru (T) standard. We report the resulting calibrated transmission and reflection at millikelvin temperatures through a printed circuit board that is installed into the sample holder. Finally, we consider a cascade of components at the end of a qubit drive line that includes (1) a cryogenic attenuator, (2) a coaxial cable, and (3) a qubit sample holder. Using experimentally determined parameters for return losses for all three components, we calculate the negligible state-preparation error in the frequency band of 5-7GHz due to control pulse distortions arising from reflection at the coaxial launches. Taken together, our results highlight the utility of calibrated cryogenic scattering parameter measurements for the validation of qubit packaging and the wiring in its immediate vicinity.

Udo Krüger Charts TechnoTeam's Journey

Udo Krüger Charts TechnoTeam's Journey

Indium and hafnium chloride modified titanium oxide thin films

Titanium oxide (TiO2) thin films were prepared by the sol-gel spin-coating technique. The influences of indium (In), hafnium (Hf), and In&Hf doping on electrochemical and structural properties were investigated. The structural properties of undoped and doped TiO2 were investigated using thermogravimetric/differential thermal (TG/DTA), X-ray Powder Diffraction (XRD), and atomic force microscopy (AFM). The optical properties were investigated using ultraviolet–visible (UV–Vis) spectroscopy, and band gap energies were calculated using the Tauc method from transmission measurement. The results showed that TiO2 had better electrochemical properties, and the band gap increased with In&Hf doping.

Effectiveness of Sn-addition on optical properties and physicochemical parameters of SnxSb2-xSe3 thin films

This research work is allocated to prepare the novel thin SnxSb2-xSe3 films, TSSe by thermal evaporation procedure at various Sn-content, where 0≤x≤2 at.%. The field-emission scanning electron microscope has been used to investigate the surface nature of these SnxSb2-xSe3 films. X-ray diffraction revealed that all TSSe films disclosed that the films have the polycrystalline nature with the orthorhombic structure without regard to the Sn-content. The optical characteristics of these layers were studied via transmission and reflection spectrophotometric measurements. The Archimedes' principle has been used to measure the density of samples, which was found that its values increase from 5.766 gm/cm3 to 6.136 gm/cm3. Along with, the molar volume decreases from 83.316 cm3/mol to 77.291 cm3/mol. The optical energy gap investigation of thin SnxSb2-xSe3 layers indicated that these layers exposed a direct allowed electronic transition. The optical band-gap energy reduces from 1.191 eV to 1.050 eV, while the band tail width increases from 0.093 eV to 0.155 eV by boosting the Sn-content. Impact of Sn-content on the linear optical parameters also refers to increasing the absorption coefficient, refractive index (from 3.2086 to 3.3317), molar refraction (from 0.756 to 0.771), the interaction strength between the electrons and photons (from 2.439 to 4.065). On the contrary, the steepness parameter, reflection factor, and electronic polarizability decrease as Sn-percentages increase from 0.0 to 2.0 at%. In addition, many other parameters have been discussed, like the optical conductivity, the real and imaginary parts of the dielectric indices, some nonlinear optical parameters, and the semiconductor-type of these films, which detect that they are p-type semiconductors. The investigated parameters and properties showed that these films can be used in many optical applications, like solar cells, photodetectors, batteries, memory devices, and others.

Characterization study of geopolymer concretes fabricated with clinker aggregates

Geopolymers are a new generation of building material that has recently been popular in reducing carbon emissions. As a result of its amorphous alumina-silicate-based reaction product, it has many superior properties. This study investigated the mechanical and physical properties and high-temperature resistance of ground-granulated blast furnace slag and metakaolin-based geopolymer concrete fabricated with clinker aggregates produced in a short curing time (8 h). In alkali activators, the sodium silicate to sodium hydroxide (SS/SH) mass ratios were 2, 2.25, 2.5 and 2.75. Two curing methods were used, namely ambient (25 °C) and oven curing (80 °C). The observed unit weights vary between 2275–2392 kg/m3 for the samples of the geopolymeric composites. Porosity and water absorption vary between 4.92 and 8.84% and 3.58–7.26%, respectively. The heat curing application decreased the mixtures' water absorption, unit weight, and porosity values. The compressive strength of the samples subject to ambient curing varied between 39.2 and 59.8 MPa. Withal, the samples cured at 80 °C for 8 h were between 66.9 and 112.4 MPa. The increased SS/SH ratio also increased the observed strength values. Capillary water absorption of all samples is below 0.6 kg/m2. Heat-cured geopolymers decreased capillary water absorption to 0.1 kg/m2. The weight loss after high temperature decreased as the SS/SH ratio increased. The N-A-S-H gel in the zeolitic structure was observed in SEM analysis. The FT-IR analysis visualized the carbonation in the heat-cured mixtures. As a result, over 100 MPa compressive strength values were observed with the clinker aggregates at 80 °C after 8 h of curing time. Withal, a high-temperature refractory composite was developed with the clinker aggregates. Moreover, the nuclear radiation shielding abilities of geopolymer concretes were investigated experimentally. The gamma shielding parameters of the samples were evaluated by transmission measurements in the range of 0.081–0.661 keV. Also, neutron dose measurements were performed, and the samples produced as neutron attenuator capacity was evaluated. The radiation shielding capabilities were improved slightly with increasing sodium silicate solution content.

Near-field measurements for wood anisotropy using cavity-backed slot antennas

Wood is becoming a very important structural material for buildings because it is a renewable resource and has a very small carbon footprint. This paper reports an experimental study on the effect of annual rings on wood anisotropy measurements using near-field microwave scanning for Pine, Hemlock, Red Cedar, and Hardwood laminated wood beams. Transmission measurements show significant anisotropy (>10 dB) for Pine wood compared to Hemlock wood and Red Cedar wood for linear polarization. The effect of annual rings in guiding the transmitted signal through wood fibers is observed through transmission measurements. Microwave guidance in transmission disappears with increasing the moisture content (17%–138%) of the Pine wood sample. The study provides a novel, accurate, fast, low-cost structural-wood testing method based on cavity-backed slot antennas for transmission and reflection measurements.

Factors influencing the electromagnetic transmission of mercury vapor discharge plasma tube arrays

Low-pressure Mercury vapor discharge plasma tubes were used to form arrays to control electromagnetic transmission. The internal and external factors influencing a discharge tube array were adjusted to expand the electromagnetic wave manipulation ability. The plasma electron density (n e) is the key parameter for electromagnetic wave manipulation. Microwave transmission was used to diagnose n e under different working conditions. Simulations and electromagnetic transmission measurements were used to investigate the behavior of the effect of internal and external factors on electromagnetic transmission. Simulation results indicated that increasing n e increased the attenuation, widened the attenuation bandwidth, and shifted the attenuation band to higher fRequencies. The experimental results showed that increasing the discharge power significantly increased n e and widened the strong attenuation frequency band. n e first increased and then decreased when the gas pressure was increased. The tube diameter affected both n e and the plasma layer thickness, and the attenuation band of the plasma tube array moved to a low frequency with an increase in tube diameter. The primary and secondary order of the influence of external factors other than power on the attenuation bandwidth obtained via an orthogonal experiment is as follows: gas composition > tube diameter > pressure. The maximum attenuation bandwidth for 10 dB attenuation was 9.85 GHz. The results show that the attenuation control ability of the plasma tube array can be significantly improved by adjusting the external factors of the plasma tube.

Terahertz reflection hyperspectral 3D imaging using beam scanning.

Terahertz (THz) radiation has the capability to combine spectroscopy and imaging in a single system. The resulting hyperspectral images can reveal concealed objects and identify materials by means of characteristic spectral features. For security applications, THz is attractive for its non-contact and non-destructive measurement capabilities. For such applications, objects may be too absorbing for transmission measurements, or only one side of an object may be accessible, necessitating a reflection measurement configuration. This work details the development and demonstration of a compact fiber-coupled hyperspectral imaging reflection system suited to field use for security and industrial applications. The system uses beam steering to measure objects of up to 150 mm diameter with a depth range of up to 255 mm, allowing for 3-dimensional mapping of objects, while simultaneously acquiring spectral data. Spectral information between 0.2-1.8 THz is extracted from a hyperspectral image and used to identify lactose, tartaric acid, and 4-aminobenzoic acid in high and low humidity environments.

Optical and flexoelectric biosensing based on a hybrid-aligned liquid crystal of anomalously small bend elastic constant

Liquid crystal (LC)-based biosensors rely on the response of the LC molecules to perturbation generated by analytes at the interface, leading to the susceptible change in molecular alignment or orientation. The sensitivity of these biosensors is primarily dependent on the LC's material properties and surface anchoring strength. By incorporation of an unconventional mesogenic compound (CB7CB) coupled with the hybrid-alignment cell configuration, this work presents a binary nematic LC for label-free biosensing, manifesting a novel sensing technology that takes advantage of CB7CB-induced flexoelectricity in the transducer. Herein, we prepared LC mixtures by blending a typical rod-like nematic LC (E7) with the bent-core mesogen CB7CB in various weight ratios and studied the effect of the CB7CB content on E7/CB7CB-based biosensing performance in vertically aligned and hybrid-aligned nematic (HAN) cells. Owing to the anomalously small bend elastic constant K33 in CB7CB, the mixture designated CB45 with the highest CB7CB weight percentage (45 wt% in this study) was best applicable to biosensing in HAN cells. When observed under a polarizing optical microscope, CB45 in the HAN geometry showed the capability of detection of as low as 10−10 g/mL for the protein standard bovine serum albumin (BSA). Moreover, the quantitation of the assay was fulfilled by both dielectric and light transmission measurements of the hybrid-aligned cholesteric CB45/R5011. The limit of detection of 7 × 10−10 g/mL was achieved by spectrometric analysis. To the best of our knowledge, this work is the first to demonstrate flexoelectric biosensing on the basis of flexoelectric polarization associated with giant flexoelectricity in CB7CB partially constituting the LC transducer.

Structural characterization of AlN thin films grown on sapphire by atomic layer deposition

In this article, two sets of AlN thin films were produced on sapphire wafers with diverse surface orientations (C-, M-, R-, and A-) via atomic layer deposition. Various material characterization techniques were applied to investigate the morphological, structural, and optical properties of the AlN films, including atomic force microscope (AFM), X-ray diffraction, Raman scattering, X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible spectrophotometer (UV–vis). The AFM results reveal that all AlN films are uniformly covered on the sapphire substrate, with no pinholes or cracks. Raman scattering spectroscopy indicates that the AlN thin films deposited on A-plane and M-plane sapphire substrates have low defect concentration. According to XPS results, the surface chemical state and element ratios of the AlN films produced on sapphire substrates with varied surface orientations are constant. The results of UV–vis transmission measurements show that the AlN film on M-plane sapphire substrate has the highest transmittance.

Detection and quantification of alkali-silica-reaction (ASR) gel in cement-based mortars using microwave spectral and temporal transmission properties

Microwave transmission measurements in time-domain, as a new measurement tool, were carried out to detect and quantify alkali-silica-reaction (ASR) within mortar specimens. To examine the potential of time-domain transmission measurements for ASR detection and its any possible quantification, transmission measurements in frequency-domain and time-domain of two different sets (reactive and non-reactive) of mortar specimens were performed approximately every 2 or 3 days over 29 days after demolding the specimens, by a rectangular waveguide operated at 2.60–3.95 GHz. Thickness expansion measurements of reactive and non-reactive sets were also performed. Additionally, SEM micrographs and energy-dispersive X-ray spectroscopy tests of specimens were implemented to support microwave and expansion measurements. After performing some analysis for the correlation between microwave and expansion measurements, it is observed for the first time in the literature that transmission measurements via expansion tests could be effectively applied for quantification of ASR level within cement-based materials.

Low‐Temperature Synthesis of Silicon Oxynitride‐Doped Si for Tunable Bragg Gratings Homogeneously Deposited on Si, SiO2, and Borosilicate Substrates and the tip of SM and PM Optical Fibers

AbstractOptical tunability and repeatability are essential in fabricating optoelectronic devices from waveguides to Bragg gratings (BGs) for high‐energy, high‐power, mode‐locking, and sensing applications. For this purpose, a controlled adjustment in the optical properties, including the refractive index of the deposited nanolayers, becomes critical. This study reveals that silicon oxynitride (SiON) doping into silicon (Si) offers a new way for the preparation of novel Si‐based devices with an emphasis on the BGs for filtering a particular portion of an electromagnetic spectrum, including the wavelengths of 800, 976, 1550, and 1840 nm. Control on the incident angle dependence of the BGs is demonstrated at Watt‐level for the wavelength of 976 nm. Amorphous SiON‐doped Si layers on alternating SiO2 can be synthesized on bulk substrates and different optical fibers at relatively low temperatures with wide and narrow bandwidths. The high reflectivity of the novel Si‐based BGs reveals over −22 dB reflection using typical optical fibers, including standardsingle‐mode fibers and high‐birefringent polarization‐maintaining (PM) fibers. The polarized transmission measurement over the BG on the PMfiber shows the BGs do not deteriorate the PM properties, strongly yielding a beat length of 1.68 mm and birefringence of 9.2 × 10−4 at the telecom C band.

Study on the Test and Evaluation Technology for Multi-weapon Actual Combat Effectiveness in Multi-domains

In view of the new characteristics and demands presented in the actual combat training assessment of our troops in recent years, such as fast attack of weapons and ammunitions, wide attack range, multi-bomb attack multi-target, low missing test rate, giving the assessment results quickly, etc., the disadvantages of the current attack effectiveness and evaluation system are analyzed. In this paper, multi-aperture integration optical measuring station, radar and unmanned aerial vehicle (UAV) three-dimensional measurement technology, higher adaptive broadband transmission technology, measurement and control network based on cloud computing technology are explored. The aim is to promote the current single projectile effectiveness test system to multi-weapon combat effectiveness test and evaluation system, which will improve the training level of our troops rapidly.

Synthesis of Broadband Oversized Miter Bend for High-Power Millimeter Wave System

An optimum approach for designing a TE01 mode broadband oversized miter bend is proposed by synthesizing a mixture beam with the characteristics of conical Gaussian beam. With the analysis of the characteristics realized by the simple mixture modes based on the gap theory, the optimized mixture mode under different waveguide dimensions for high transmission efficiency miter bend is deduced. According to the analysis results and the broadband mode synthesis technology, a Ka -band oversized waveguide miter bend propagating circular TE01 mode is designed, fabricated, and measured. According to the transmission measurement results, the miter bend can achieve the transmission efficiency up to 95% in the frequency range of 32–38 GHz, which verifies the broadband and high-efficient characteristic of the component. The near-field test results further demonstrate the high output vector purity of the TE01 mode over 95.5% and the scalar purity over 98% is acquired in the working frequency band.

Synthesizing pseudo-Kossel lines from neutron transmission data. II. Validation with neutron diffraction data

A new method to recover the orientation matrix of a single crystal with a known unit cell by analyzing synthesized pseudo-Kossel lines from time-of-flight neutron transmission data has been outlined in a companion article [Dessieux et al. (2023). J. Appl. Cryst. 56, https://dx.doi.org/10.1107/S1600576723001346; referred to here as Article I]. In this work, validation of this new technique is presented by employing experimental neutron transmission and diffraction measurements performed on two copper single-crystal specimens. Time-of-flight spectra were recorded during rotation (ω) of the single crystals about a vertical axis perpendicular to the incident neutron beam. The λ–ω maps recorded in transmission are utilized to determine the crystal orientation with respect to the neutron beam, following the procedure presented in Article I. To validate the indexing procedure, the crystal orientations are compared with those obtained via conventional methods using the diffraction data. The resulting pseudo-Kossel lines across the 2D detectors are also observed for the first time.

Comparative Performance Analysis of Femtosecond-Laser-Written Diode-Pumped Pr:LiLuF4 Visible Waveguide Lasers

In this work, we present the operation of a femtosecond-laser-written diode-pumped visible waveguide laser based on praseodymium-doped lithium lutetium fluoride. The refractive index modification induced by the femtosecond laser in the crystal exhibits an anisotropic behavior, thus enabling the fabrication of different types of waveguides from single-track structures to stress-induced waveguides and depressed cladding structures. All the waveguides were characterized by realizing transmission measurements and the waveguide design was optimized to obtain extremely low propagation losses, equal to 0.12 dB/cm. Lasing has been achieved at 604 nm and 721 nm from different waveguides. In addition, stable continuous-wave lasing at 698 nm has been obtained in a depressed cladding waveguide. This wavelength corresponds to the one needed for the transition of the atomic clock based on the neutral strontium atom. In the end, we report the observation of laser emission at 645 nm from a depressed cladding waveguide.

Optical and dispersion studies of thin S35-xGe15SnxTe50 films: Assessment of some physical parameters of samples

This article presents a study on the optical and dispersion characteristics of a group of thin films with exciting potential for optical applications. Thermally evaporated a-S35−xGe15SnxTe50 thin films (SGST) where x ranges from 0 to 10 at.% have been investigated. XRD, EDX, and FE-SEM techniques are utilized to examine the samples’ physical properties. Meanwhile, optical characteristics are studied in the 300–2500 nm region through transmission and reflection measurements. Experimental and theoretical methods were employed to determine the optical bandgap energies (Eg), indicating that the films’ electronic transition is indirectly allowed. The Eg-values decreased as Sn-content increased, reaching a range of 1.031 eV to 1.301 eV, while the refractive index increased from 2.513 to 2.741. In addition, the Wemple-Di-Domenico model was used to determine the dispersion energies (Eo and Ed), and it is found that they decreased as Sn-content increased, from 2.014 eV to 2.672 eV for Eo, and from 13.009 eV to 15.334 eV for Ed. Many other important parameters, such as the average heat of atomization, total mean bond energy, and deviation from stoichiometry, are also calculated and discussed. The results of this investigation suggest that these SGST samples could be used in various optical applications and provide a basis for further research and innovation in this exciting field.