Special section guest editorial: advances in terahertz biomedical science and applications

The Journal of Biomedical Optics (JBO) has published this special section of papers to capture the most recent advances in THz technology and innovative THz instruments and methods in biology and medicine. A few of the papers in this special section are dedicated to similar biomedical applications of novel optical tools from the neighboring infrared (IR) range. Two papers of the special section consider modern problems of oncodiagnosis. In the research article ‘Development of oral cancer tissue-mimicking phantom based on polyvinyl chloride plastisol and graphite for terahertz frequencies’, authors have introduced a new type of a water-free tissue-mimicking phantom for THz biophotonics. This phantom is based on graphite powders embedded into a polyvinyl chloride plastisol matrix. The effective THz optical properties of such a phantom can be managed in a wide range by changing its composition, thus allowing to mimic the THz optical properties of various biological tissues

Numerical Analysis of Liquid Menisci in the EFG Technique

This chapter is devoted to the analysis of the behavior of the profile curves of the melt menisci for the sapphire crystal growth by edge-defined film-fed growth (EFG) technique. The menisci of the shaped crystals with capillary channels, fibers, and tubes (including cases of outer and inner circular menisci) are considered. Also, we investigated the profile curves of menisci both in the cases of the positive and negative angles between profile curve and the working edge of the die. The cases of outer and inner circular menisci of the tubular crystals and menisci at capillaries and fibers are considered

Influence of the geometric parameters of the electrical ring resonator metasurface on the performance of metamaterial absorbers for terahertz applications

\u3cp\u3eIn this paper, the effect of the geometrical parameters of an electrical ring resonator(ERR) on the total absorptivity of metamaterial absorbers is analyzed. In particular, the effect of electrical ring resonator parameters, dielectric layer(spacer) thickness and electrical ring resonator thickness on the absorber of metamaterials are analyzed in detail. On this basis, the orthogonal experiment is set up to analyze the combined effects of several parameters and finally obtain the theoretical absorptivity of metamaterials. Based on the above results, the principle prototype of two metamaterial absorbers is prepared. The results show that the narrowband absorptivity of the prototype is higher than 98%, which provide guidance for the design of high performance absorber.\u3c/p\u3

Continuously tunable middle-IR bandpass filters based on gradient metal-hole arrays for multispectral sensing and thermography

Continuously tunable middle-infrared bandpass filters have been developed based on gradient metal-hole arrays with two distinct geometries. The rotation filter relies on an array of metal holes with gradually changing periods and hole sizes in the azimuthal direction, while the translation filter exploits a metal-hole array with a linear gradient. The filters are fabricated in a Ti film on a ZnSe substrate using electron- beam nanolithography. They are characterized experimentally using Fourier-transform infrared spectroscopy, and the observed results are compared with numerical predictions of the finite element method. The developed filters offer wide spectral tunability when operating with a focused beam. Particularly, the central wavelength of the transmission band is tunable in the λc [ ð9, 15Þ μm range, for the rotation filter, and in the λc [ ð8, 13Þ μm range for the translation one, as a linear function of the filter angular or linear displacement. The filters feature relatively broad bandwidths of Δλ ≃ 0:2λc, while their spectral contrast and energy efficiency depend on the gradient type. The filter spectral response function shape and the extent of its spectra tunability can be further optimized by judicious design of the hole geometry and the metal-hole array gradient, respectively. The developed filters hold strong potential in the infrared multispectral sensing and imaging, thanks to their conceptual simplicity. Considering the linearity of Maxwell’s equations and availability of appropriate technologies for the fabrication of gradient arrays of sub-wavelength metal holes, the developed concept can be translated to other spectral ranges

Observation of WWW Production in pp Collisions at √s = 13 TeV with the ATLAS Detector

This Letter reports the observation of W W W production and a measurement of its cross section using 139     fb − 1 of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. Events with two same-sign leptons (electrons or muons) and at least two jets, as well as events with three charged leptons, are selected. A multivariate technique is then used to discriminate between signal and background events. Events from W W W production are observed with a significance of 8.0 standard deviations, where the expectation is 5.4 standard deviations. The inclusive W W W production cross section is measured to be 820 ± 100   ( stat ) ± 80   ( syst )     fb , approximately 2.6 standard deviations from the predicted cross section of 511 ± 18     fb calculated at next-to-leading-order QCD and leading-order electroweak accuracy

Measurements of the Total and Differential Higgs Boson Production Cross Sections Combining the H??????? and H???ZZ*???4??? Decay Channels at s\sqrt{s}=8??????TeV with the ATLAS Detector

Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3~fb$^{-1}$ of $pp$ collisions produced by the Large Hadron Collider at a center-of-mass energy of $\sqrt{s} = 8$ TeV and recorded by the ATLAS detector. Cross sections are obtained from measured $H \rightarrow \gamma \gamma$ and $H \rightarrow ZZ ^{*}\rightarrow 4\ell$ event yields, which are combined accounting for detector efficiencies, fiducial acceptances and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be $\sigma_{pp \to H} = 33.0 \pm 5.3 \, ({\rm stat}) \pm 1.6 \, ({\rm sys}) \mathrm{pb}$. The measurements are compared to state-of-the-art predictions.Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3  fb-1 of pp collisions produced by the Large Hadron Collider at a center-of-mass energy of s=8  TeV and recorded by the ATLAS detector. Cross sections are obtained from measured H→γγ and H→ZZ*→4ℓ event yields, which are combined accounting for detector efficiencies, fiducial acceptances, and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be σpp→H=33.0±5.3 (stat)±1.6 (syst)  pb. The measurements are compared to state-of-the-art predictions.Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3 fb$^{-1}$ of $pp$ collisions produced by the Large Hadron Collider at a center-of-mass energy of $\sqrt{s} = 8$ TeV and recorded by the ATLAS detector. Cross sections are obtained from measured $H \rightarrow \gamma \gamma$ and $H \rightarrow ZZ ^{*}\rightarrow 4\ell$ event yields, which are combined accounting for detector efficiencies, fiducial acceptances and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be $\sigma_{pp \to H} = 33.0 \pm 5.3 \, ({\rm stat}) \pm 1.6 \, ({\rm sys}) \mathrm{pb}$. The measurements are compared to state-of-the-art predictions