This work presents a compact LiNbO3 (lithium niobate, LN) electro-optic (EO) Q-switch with a lower driving voltage than the conventional LN Q-switches. By using non-direct cuts of a certain crystallographic orientation, a LN crystal is used both as a quarter-wave plate (QWP) and a pockels cell in a laser cavity. Through theoretical calculations and experiments, we have determined the optimized crystal orientations with low quarter-wave voltages (QWV). A set of compact LN EO Q-switches were prepared and used successfully in the pulse-on mode in a NdYAG laser. The Q-switched laser outputs are comparable to those obtained by using a conventional Z-cut LN Q-switch with a QWP. The QWV of the Q-switch with the optimized crystal orientation is 600V lower than that of the Z-cut LN Q-switch.We numerically analyze superradiant dynamics in atomic ensembles that have different transition frequencies using a numerical model that can take account of the transient behavior of an unsynchronized superradiant state. The numerical results unveil that the superradiant emission of a periodic pulse train can be induced by means of collective multiple frequency generation, which we call superradiant mixing. This is, in fact, due to the superradiant coupling of unsynchronized atomic ensembles. We numerically investigate the superradiant mixing in detail, varying the collective decay rate, repumping rate, and the number of the individual atomic ensembles with detuned frequencies. This work broadens our understanding of the collective atomic behavior in a detuned system, and it also suggests a novel method for frequency generation without relying on the conventional Kerr nonlinear effect.The problem of a vertical electric dipole radiating above a periodic multilayer whose unit cell comprises a layer of a topological insulator (TI) and a columnar thin film (CTF) was solved in order to investigate the left/right asymmetry of the total electric field in the far zone in the half-space containing the dipole. Occurring in a wide range of the polar observation angle, the left/right asymmetry of Eϕ is due to both the CTFs and the TI layers. Occurring in a narrow range of the polar observation angle, the left/right asymmetry of Eθ is entirely due to the TI layers. For presently available values of the magnitude of the surface admittance γTI of TIs, significant left/right asymmetry occurs if the number of unit cells in the periodic TI/CTF multilayer is high enough.In this erratum, we correct two minor algebraic errors from our previous published manuscript [Opt. Express 27, 35189 (2019)], which do not affect the main results or conclusions, and make a corresponding small change to one figure.Imaging using terahertz time-domain spectroscopy is a valuable diagnostic tool for material inspection. However, in the case of samples with inhomogeneous shape and composition, the reliable extraction of spatially varying dielectric properties can be very challenging. Here, we demonstrate a new approach which combines THz-TDS with photogrammetric reconstruction. We show that this technique can be used to estimate the local refractive index of samples with a complex geometry. We employ this method to study samples of ancient pottery, and demonstrate that THz techniques can provide a valuable new tool for this branch of archaeological science.This paper presents a theoretical and numerical study of a 0-π fan-out phase grating placed in the Fourier plane of a spatio-spectral pulse shaper followed by a spherical focusing lens. It is shown that this device acts as a high complexity femtosecond pulse duplicator designed for two source interferometry. At the focus of the lens, the electric field displays two spatially separated intense spots in which relative delay can be continuously tuned over 4 orders of magnitude, typically from a few attoseconds to a few tens of femtoseconds. Because the two pulses do not spatially overlap, their intensity remains unchanged when the relative delay is smaller than the pulse duration. Detailed simulations of the shaped electric field are presented.Using the improved quantitative rescattering (QRS) model, we simulate the correlated two-electron momentum distributions (CMD) for nonsequential double ionization (NSDI) of Ar by near-single-cycle laser pulses with a wavelength of 750 nm at an intensity of 2.8 × 1014 W/cm2. With the accurate cross sections obtained from fully quantum mechanical calculations for both electron impact excitation and electron impact ionization of Ar+, we unambiguously identify the contributions from recollision direct ionization (RDI) and recollision excitation with subsequent ionization (RESI). Our analysis reveals that RESI constitutes the main contribution to NSDI of Ar under the conditions considered here. The simulated results are directly compared with experimental measurements [Bergues et al., Nature Commun. 3, 813 (2012)] in which each NSDI event is tagged with the carrier-envelope phase (CEP). It is found that the overall pattern of both the CEP-resolved and the CEP-averaged CMDs measured in experiment are well reproduced by the QRS model, and the cross-shaped structure in the CEP-averaged CMD is attributed to the strong forward scattering of the recolliding electron as well as the depletion effect in tunneling ionization of the electron from an excited state of the parent ion.The regulation of the local structure around Er3+ ions is an important channel for adjusting the characteristic of up-conversion luminescence. In this paper, the cubic-phased Er3+CaF2 crystals with different Er3+ doping concentrations were fabricated with temperature gradient technique (TGT) method and the effect of the local coordination structure of the Er3+ ions on its luminescence performance was investigated.  https://www.selleckchem.com/products/OSI-906.html  The local coordination structure of Er3+ ions was simulated by density functional theory. The computational results show that clusters evolve from low order to high order with the increase of Er3+ ion doping concentration. In this evolution process, the local structure transforms from cubic structure to the co-existence of cubic and lower symmetric square anti-prism structures. Meanwhile, the distance between Er3+ ions in the cluster decreased first and then increased slightly, and in dimers and trimers this distance reached the minimum. Under 980 nm excitation, with the increase of Er3+ ion concentration, the intensity ratios of the red and green emissions of Er3+CaF2 first increased from 0.