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Doping β-tricalcium phosphate (β-TCP) with copper (Cu²⁺) has great potential in various applications due to its rich chemistry. However, the doping characteristics are rarely studied in detail and are yet to be fully understood, creating a gap in the existing knowledge of these multifunctional materials. In this work, a series of Cu²⁺ doped β-TCP (Cu_x-TCPs) were prepared and comprehensively characterized to investigate the correlation between Cu²⁺ doping and the material properties. Also, the synthesis of Cu_x-TCPs was modeled using thermodynamic equilibrium calculations to investigate their formation pathways. The calculations predicted a possible inclusion of Cu²⁺ in intermediate phosphate phases during the material synthesis, depending on the temperature. The structural analyses revealed lattice shrinkage due to the Cu²⁺ doping and that Cu²⁺ occupied Ca4 and Ca5 sites in the β-TCP crystal. The vibrational spectroscopy of the Cu_x-TCPs showed noticeable deformation of ν₁ band of PO₄³⁻ ligand. The ultraviolet-visible absorption analysis revealed a reduction in the band gap energy induced by Cu²⁺ doping. Photoluminescence spectroscopy demonstrated an enhanced emission tunability of Cu_x-TCPs in the blue and orange–red regions depending on Cu²⁺ concentration. These findings are a step toward a deeper understanding of the structure–property relationships of Cu²⁺ doped β-TCPs and can play a significant role in their multidisciplinary applications.

In this study, the impact of Zn2+ doping on β-Ca3(PO4)2 characteristics was investigated with particular focus on its influence on the surface, structure, and photocatalytic properties. Zn2+ doped β-Ca3(PO4)2 (Znx-TCPs) were synthesized using a solid-state method and were thoroughly studied to evaluate the modification induced by cationic substitution. The structural analysis revealed a noticeable shrinkage in the lattice parameters a and c and the unit cell volume induced by Zn2+ doping. Minor spectral changes in the vibrational modes of PO43− were also observed in the infrared and Raman spectra of Znx-TCPs. The influence of doping on the materials’ morphology was insignificant; however, molten grain boundaries were noticeable at high Zn concentration, x ≥ 1. X-ray photoelectron spectroscopy (XPS) revealed that the surface of the doped materials was rich in Zn. Optical absorption measurements indicated that Zn2+ doping slightly affects the optical bandgap of β-Ca3(PO4)2. The photocatalytic activities of the materials were investigated for the degradation of Rhodamine B (RB) and Methylene blue (MB). The photocatalytic experiments were carried out in the presence of hydrogen peroxide and under simulated solar light. The samples exhibited enhanced catalytic activity compared to β-Ca3(PO4)2, and the Zn0.5-TCP sample demonstrated the highest degradation efficiency. This sample showed excellent stability during the reusability tests, which suggests the suitability of Zn0.5-TCP for use as an efficient photocatalyst. Surface defects are believed to play an important role in the production of active species during the photocatalytic reaction.

Ultrahigh peak-power laser systems with pulse durations of tens of femtoseconds are widely used as drivers for compact sources of particles and secondary radiation. Conversely, lasers with shorter (a few femtoseconds) pulse durations and lower peak powers enable the generation of isolated attosecond light pulses to study nature with unparalleled temporal resolution. Here we report an enhanced optical parametric chirped pulse amplifier system that produces light pulses with a peak power of about 100 TW and a pulse duration as short as 4.3 fs with full waveform control. Coherent field synthesis generates a broadband spectrum, spanning from the visible to the near infrared, through three cascaded amplification stages, each housing two optical parametric amplifiers that sequentially boost complementary spectral regions. The resulting light transients are waveform-stabilized to <300 mrad and focused to an intensity of 1021 W cm−2 and exhibit an outstanding high dynamic range in temporal contrast. Together, these characteristics render the system well suited for demanding relativistic laser–plasma experiments. Utilizing temporal super-resolution, the pulses are shortened to sub-4-fs duration. This platform is dedicated to advancing the frontiers of attosecond electron and X-ray sources.

Introduction: Polymethyl methacrylate is a polymer commonly used in clinicaldentistry, including denture bases, occlusal splints and orthodontic retainers.

Methods: To augment the polymethyl methacrylate-based dental appliances incounteracting dental caries, we designed a polymer blend film composed ofpolymethyl methacrylate and polyethylene oxide by solution casting and addedsodium fluoride.

Results: Polyethylene oxide facilitated the dispersion of sodium fluoride,decreased the surface average roughness, and positively influenced thehydrophilicity of the films. The blend film made of polymethyl methacrylate,polyethylene oxide and NaF with a mass ratio of 10: 1: 0.3 showed sustainedrelease of fluoride ions and acceptable cytotoxicity. Antibacterial activity of all thefilms to Streptococcus mutans was negligible.

Discussion: This study demonstrated that the polymer blends of polyethyleneoxide and polymethyl methacrylate could realize the relatively steady release offluoride ions with high biocompatibility. This strategy has promising potential toendow dental appliances with anti-cariogenicity.

Nickel (II) oxide, NiO, is a wide band gap Mott insulator characterized by strong Coulomb repulsion between d-electrons and displays antiferromagnetic order at room temperature. NiO has gained attention in recent years as a very promising candidate for applications in a broad set of areas, including chemistry and metallurgy to spintronics and energy harvesting. Here, we report on the fabrication of polycrystalline NiO using spray-pyrolysis technique, which is a deposition technique able to produce quite uniform films of pure and crystalline materials without the need of high vacuum or inert atmospheres. The composition and structure of the NiO thin films were then studied using x-ray diffraction, and atomic force and scanning electron microscopies (SEM). The phononic and magnonic properties of the NiO thin films were also studied via Raman spectroscopy, and the ultrafast electron dynamics by using optical pump probe spectroscopy. We found that the NiO samples display the same phonon and magnon excitations expected for single crystal NiO at room temperature, and that electron dynamics in our system is like those of previously reported NiO mono- and polycrystalline systems synthesized using different techniques. These results prove that spray-pyrolysis can be used as affordable and large-scale fabrication technique to synthesize strongly correlated materials for a large set of applications.

The spectral phase and amplitude of a multi-TW laser with a Fourier transform limit of 4.6 fs was optimized to obtain 3.9 fs pulses with >5TW, providing the most energetic sub-4-fs pulses in the world.

Plasmonic nanometasurfaces/nanostructures possess strong electromagnetic field enhancement caused by resonant oscillations of free electrons, and has been extensively applied in biosensing, nanophotonic and photocatalysis. However, fabrication of uniform nanostructured metasurfaces by conventional methods is complicated and costly, which mitigates a wide-spread use of this technique in ubiquitous applications. Here, we present a facile and scalable method to fabricate an active nanotrench plasmonic gold substrate. The surface comprises sub-10 nm plasmonic nanogaps and their formation is assisted by a pre-fabrication of nano-imprinted polymer nano-well arrays. The plasmonic metasurface is optimized to maximize the density of the nano-trenches by tuning the substrate material, imprinting procedure and film deposition. We show that the surface Raman enhancement due to plasmonic resonances correlates well with trench density and reach a meritorious enhancement factor of EF > 105 over large surfaces.

We further show that the electric field strength at the nanotrench features are well explained by finite element method simulations using COMSOL Multiphysics. The plasmonic substrate is transparent in the visible spectrum and conductive. In combination with a scalable bottom-up fabrication the plasmonic metasurface opens up for a wider use of the sensitive and reliable SERS substrate in applications such as portable sensing devices and for future internet of things.

The Fourier-transform limit achieved by a linear spectral phase is the typical optimum by the generation of ultrashort light pulses. It provides the highest possible intensity, however, not the shortest full width at half maximum of the pulse duration, which is relevant for many experiments. The approach for achieving shorter pulses than the original Fourier limit is termed temporal superresolution. We demonstrate this approach by shaping the spectral phase of light from an optical parametric chirped pulse amplifier and generate sub-Fourier limited pulses. We also realize it in a simpler way by controlling only the amplitude of the spectrum, producing a shorter Fourier-limited duration. Furthermore, we apply this technique to an optical parametric synthesizer and generate multi-TW sub-4-fs light pulses. This light source is a promising tool for generating intense and isolated attosecond light and electron pulses.

Optical parametric chirped-pulse amplification (OPCPA) [1] is an established light amplification technique with many beneficial properties, like high single pass gain, scalability, large spectral bandwidth, tunability and good conversion efficiency. Different methods have been proposed for optimization of conversion [2] - [4] mainly altering the pump or the crystal properties. However, seed manipulation to increase the OPCPA conversion efficiency has been only described in a general spatiotemporal field optimization theory so far [5]. Here, we show numerical and experimental results of a novel method to improve the gain saturation in an ultra-broadband OPCPA, hence conversion efficiency, by applying an adaptive spectral filter function to the seed pulses.

Optical parametric chirped-pulse amplification (OPCPA) is a light amplification technique that provides the combination of broad spectral gain bandwidth and large energy, directly supporting few-cycle pulses with multi-terawatt (TW) peak powers. Saturation in an OPCPA increases the stability and conversion efficiency of the system. However, distinct spectral components experience different gain and do not saturate under the same conditions, which reduces performance. Here, we describe a simple and robust approach to control the saturation for all spectral components. The demonstrated optimal saturation increases the overall gain, conversion efficiency and spectral bandwidth. We experimentally obtain an improvement of the pulse energy by more than 18%. This technique is easily implemented in any existing OPCPA system with a pulse shaper to maximize its output.