Journal of Russian Laser Research最新文献

To improve the surface performance of 6061 Aluminum alloy, Graphene (Gr)/high entropy alloys (HEAs) coatings were prepared on its surface using laser additive manufacturing technology. The experimental results show that the Gr/AlCoCrFeTiCu_x coatings are mainly composed of equiaxed crystals, with Gr playing a strengthening role and Cu element playing a fine grain strengthening role. The coating has excellent mechanical properties and corrosion resistance. The microhardness is between 439 and 453 HV and average friction coefficient is between 0.43 and 0.50, while the self-corrosion potential is between −1.13 and 0.94 V and the self-corrosion current densitya is between 3.78 · 10⁻⁴ and 7.59 · 10⁻⁵ A/cm². Our investigation shows that laser additive manufacturing Gr/AlCoCrFeTiCu_x coatings on 6061 Aluminum surfaces can effectively improve their surface properties.

This study investigates the influence of nanoparticle shape on the third-order nonlinear optical properties of silver nanostructures, specifically focusing on spherical nanoparticles and triangular nanoplates synthesized via a self-seeding growth method. Also, we report the strongly pronounced dependence of the nonlinear absorption coefficient on laser beam intensity for both morphologies. Open-aperture z‑scan measurements, performed at 532 nm within the absorption band of the study materials, reveal distinct plasmonic features and significant contributions to the increase in normalized transmittance for spherical Ag NPs. The physical mechanisms underlying this intensity dependence are discussed, and the extracted nonlinear absorption coefficients are compared, providing insight into the role of geometric anisotropy in modulating nonlinear optical responses. These findings, which differ from previously reported works, contribute to a broader understanding of shape-engineered plasmonic nanomaterials and their potential in photonic and optoelectronic applications.

We present findings on photon antibunching and sub-Poissonian photon statistics in both the fundamental (pump) and harmonic modes, investigated up to first- and second-order Hamiltonian interactions in the context of eighth harmonic generation (EHG). Utilising the Heisenberg picture, a generalised interaction Hamiltonian is formulated and analysed across multiple specific scenarios. Our study focuses on the emergence of photon antibunching during short interactions. Notably, third-order photon antibunching at short timescales reveals a deeper degree of nonclassicality than that seen in first- and second-order cases. Enhanced nonclassical phenomena are observed under first-order coupling interactions due to the coherent entanglement of pump and harmonic fields. Furthermore, coherent or vacuum pumping leads to noticeable photon bunching in the harmonic mode. Sub-Poissonian characteristics intensify with increasing pump photon counts, emphasising that higher-order interactions significantly support the generation of nonclassical states. Minimising the second-order correlation function remains pivotal in quantum optics to realise photon antibunching.

An exact solution of the problem of two 2‑level atoms interacting with two mode field is obtained. For a chosen initial states, the effects of the mean photon number difference on the purity loss of the subsystem are considered. The atom-field entanglement is investigated on the basis of the reduced linear atomic entropy. For this system, we investigate the negativity as a measure of entanglement.

Pulsed laser annealing (PLA) constitutes a powerful tool for nonequilibrium engineering of thin-film semiconductor properties. In this work, we investigate the impact of deep gold doping on the structural evolution and electronic properties of amorphous silicon films (α-Si:Au) subjected to nanosecond-scale PLA. Gold is shown to play a dual physical role: first, it effectively suppresses crystallite coalescence, limiting crystallite size to 2.3–2.8 nm and preserving a heterophase structure with a high crystalline fraction (up to 78%), as quantitatively corroborated by Raman spectroscopy and the phonon confinement model; second, at concentrations of approximately ~ 5 · 10²⁰ cm^-3, gold promotes the formation of a degenerate electron gas, manifesting as metallic-like behavior in the mid-infrared spectral range (2.5–5.0 µm). Key transport parameters—namely, carrier mobility (leftlangle upmu rightrangle =76pm 8,mathrm{cm}^{2}/left(mathrm{V}cdot mathrm{s}right)leftlangle upmu rightrangle =76pm 8,mathrm{cm}^{2}/left(mathrm{V}cdot mathrm{s}right)) and resistivity ⟨ρ⟩ = (1.7 ± 0.2) · 10⁻⁴ Ω · cm—were extracted from reflectance spectra using the Drude model. Despite the high density of defects and amorphous interlayers, the system achieves metallic conductivity owing to the elevated concentration of free carriers. These findings demonstrate the feasibility of synergistically tailoring both the nanostructure and electronic properties of silicon through the combined strategy of deep doping and ultrafast thermal processing, thereby opening new avenues for the development of functional silicon-based nanocomposites in optoelectronics and nanoelectronics.

To understand the physical process of effective free carrier in silicon waveguide and silicon Raman laser, the numerical simulation on the output characteristics of effective free carrier with different parameters is performed in this paper. Based on the in silicon-on-insulator (SOI) waveguides, the free carrier density as a function of length along silicon with different pump power, free charge carrier lifetime, and effective mode area of the SOI waveguide are presented. In addition, the output characteristics of continuous-wave (CW) silicon Raman silicon laser with free carrier is investigated. The numerical simulation results reveal that the output efficiency of the Raman laser could be effectively improved by reducing the free carriers.

The study of quantum light states has been a fundamental area of research, with squeezed states—specifically squeezed coherent and squeezed vacuum states, being of particular interest. This paper delves into the statistical characteristics and squeezing properties of these states, with a focus on their superposition. It is determined that the mean photon number of the combined state corresponds to the total mean photon numbers of the individual squeezed states. Additionally, when a coherent state and a squeezed vacuum state are superimposed, the resulting state behaves as a displaced squeezed vacuum state. A significant outcome is that the degree of squeezing effectively doubles due to superposition. Unlike single squeezed states, squeezing is observed for (0< r<frac{1}{2}ln 2ln).

In this paper, we introduce a quantum model of a two-qutrit (TQ) system interacting with a deformed field mode, initially prepared in a nonlinear coherent state. We analyze the quantum dynamics of TQs in a Λ-type configuration, both with and without the time-dependent coupling (TDC) effect, within the framework of the Schrödinger equation. This will help us to investigate the time evolution of intriguing phenomena such as entanglement, quantum coherence, and the precision of parameter estimation in relation to the deformation parameter and TDC effect. Specifically, we consider the quantum dynamics of negativity, von Neumann entropy, the norm of coherence, and Fisher information. Finally, we explore the interrelationships among these quantum measures, providing insights into the underlying quantum phenomena of the system.

We present results of derivations of neutron yields at the initiation of the nuclear reactions ⁹Be(gamma, n)2alpha and ¹⁸¹Та(gamma, n) ¹⁸⁰Та in the compound target consisting of the isotopes ⁹Be and ¹⁸¹Ta irradiated by the picosecond intense laser pulses. Gamma-radiation is appeared due to the Bremsstrahlung of relativistic electrons that are produced at the laser ponderomotive heating after multiple above-barrier laser ionization of target atoms. Theoretical calculations are in good agreement with the recent experimental data.

This study presents an optimization and simulation of a surface plasmon resonance-based optical fiber sensor with a D-shaped configuration, for the precise detection of aqueous nitro explosive. The proposed sensor undergoes simulation and analysis using finite element techniques. Optimization of the Au layer thickness, with a 30 nm layer identified for maximum SPR curve reflection, Subsequently, a polyaniline layer was applied to enable selective detection. Varying sample concentrations interact uniquely with the polyaniline sensing surface, as concentration increases, the SPR dip shifts toward longer wavelengths like red-shift in the spectra. Simulating sensor lengths ranging from 1 to 5 mm provides valuable insights into sensor responses, showing improved detection accuracy and figure of merit as the sensor length decreases.