Physics of Wave Phenomena最新文献

{"title":"Optimization of Pump Pulse Duration and Cr:ZnSe Crystal Length for Efficient Generation of Tunable Mid-IR Laser Radiation Pumped by Laser Diode at Room Temperature","authors":"A. Říha,&nbsp;H. Jelínková,&nbsp;M. E. Doroshenko,&nbsp;J. Šulc,&nbsp;M. Němec,&nbsp;D. Vyhlídal,&nbsp;D. V. Badikov","doi":"10.3103/S1541308X24700249","DOIUrl":"10.3103/S1541308X24700249","url":null,"abstract":"<p>The spectral and laser output characteristics of Cr:ZnSe single crystals optically polished at four different lengths of 2, 3, 5, and 10 mm combined with or without antireflection (AR) coatings were investigated under pulse and continuous wave (CW) laser diode excitation at the wavelength of ~1.7 μm. The absorption and fluorescence spectra of Cr²⁺ ions were measured at room temperature. Optimization of laser system efficiency was performed step-by-step in dependence on the active length of the crystal sample, output coupler reflectivity, the duration of the pump pulse, and the repetition rate. For a given 1 : 1 transferring optics, a 3-mm thick AR-coated Cr:ZnSe crystal was chosen as optimal in pulse mode of operation: The ~10% higher maximum slope efficiency of ~39% with respect to optical-to-optical power conversion was obtained with the 3-mm thick AR-coated sample compared to the uncoated one. The laser system was characterized by an optimal repetition rate of 10 Hz and a pump pulse duration of 20 ms selected for its best efficiency performance. In CW mode, better results were observed with a thicker sample (5 mm, AR-coated). Specifically, the output power of ~2.7 W at the wavelength of ~2.4 μm with a slope efficiency of ~24% was obtained. In this case, the <i>M</i>² beam parameter was measured as low as ~1.1 ± 0.1. Using a 0.8 mm thick MgF₂ birefringent filter plate, the laser oscillations were continuously tunable in the range of ~2.1–2.7 μm within narrow spectral linewidths (5–10 nm FWHM) and a Gaussian beam profile in both the pulse and CW regimes.</p>","PeriodicalId":732,"journal":{"name":"Physics of Wave Phenomena","volume":"32 4","pages":"257 - 267"},"PeriodicalIF":1.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142225172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dependence of Plasma Maser Emission Spectra on Azimuthal Plasma Concentration Inhomogeneity","authors":"A. E. Donets,&nbsp;V. I. Rogozhin,&nbsp;V. P. Bakhtin,&nbsp;A. B. Buleyko,&nbsp;A. G. Bykov,&nbsp;O. T. Loza,&nbsp;A. A. Ravaev","doi":"10.3103/S1541308X24700250","DOIUrl":"10.3103/S1541308X24700250","url":null,"abstract":"<p>Probe measurements of plasma generated by the thermionic cathode of the axially symmetric plasma maser are performed. Emission spectra of this plasma maser are recorded in its operation mode of a noise amplifier in the frequency band from 3 to 16 GHz at the power level of ~50 MW. It is shown that violation of azimuthal plasma concentration homogeneity leads to broadening of the emission spectrum by 30 to 100% of the central frequency. A possibility is found for pulse-to-pulse electron control of the width of the plasma maser emission spectrum in addition to the electron control of the frequency.</p>","PeriodicalId":732,"journal":{"name":"Physics of Wave Phenomena","volume":"32 4","pages":"268 - 272"},"PeriodicalIF":1.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142225173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Laser-Induced Heating of the Antiferromagnetic IrMn Layer on Generation of Terahertz Pulses in Co/WSe2-Based Spintronic Emitters","authors":"A. V. Gorbatova,&nbsp;A. M. Buryakov,&nbsp;P. Yu. Avdeev,&nbsp;E. D. Lebedeva,&nbsp;I. Yu. Pashen’kin,&nbsp;E. A. Karashtin,&nbsp;M. V. Sapozhnikov,&nbsp;E. D. Mishina","doi":"10.3103/S1541308X24700262","DOIUrl":"10.3103/S1541308X24700262","url":null,"abstract":"<p>Properties of spintronic terahertz generators based on the IrMn/Co/WSe₂ and Co/WSe₂ structures grown on sapphire substrates are investigated. It is demonstrated that the optical energy of the pump pulse plays a critical role in coercivity control and in generation of terahertz radiation by a structure with an antiferromagnetic IrMn layer. Analysis of terahertz loops of magnetic hysteresis obtained for pump energies ranging from 0.35 to 3.85 mJ/cm² has shown that laser-induced heating of IrMn up to temperatures above the blocking temperature is accompanied by an increase in spin injection from the Co layer into IrMn layer and a consequent increase in THz emission efficiency. The results show importance of further investigation of thermal laser-induced processes in antiferromagnetic-based spintronic emitters in the vicinity of critical temperatures, which is of great significance of further development of terahertz spintronic and photonic devices based on antiferromagnetic materials.</p>","PeriodicalId":732,"journal":{"name":"Physics of Wave Phenomena","volume":"32 4","pages":"273 - 279"},"PeriodicalIF":1.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of the Contribution of the Local and Nonlocal Optical Response of an Isotropic Gyrotropic Medium on the Components of the Minkowski Energy–Momentum Tensor of the Electromagnetic Field of the Self-Focusing Beam","authors":"P. S. Ryzhikov,&nbsp;V. A. Makarov","doi":"10.3103/S1541308X24700201","DOIUrl":"10.3103/S1541308X24700201","url":null,"abstract":"<p>Contributions of the terms related to the local and nonlocal nonlinear optical responses of a medium are determined in the expressions for the energy density, energy flux density, momentum density, and momentum flux density of the electromagnetic field at the self-focusing of elliptically polarized light in a nonabsorbing isotropic gyrotropic medium. It is shown that the contributions of the nonlinear optical response of the medium to the above quantities are maximal at the spatial points where during self-focusing of narrow elliptically polarized beams, radiation becomes linearly polarized, and they may be as large as one tenth of the contributions to the components of the Minkowski energy–momentum tensor of the electromagnetic field that are related to the linear local optical response of the medium to the external light field. Nonlocality of the optical response increases the components of the Minkowski energy–momentum tensor of the electromagnetic field in some regions of the space and decreases them in the rest of them due to the sign reversal of the degree of the self-focusing beam ellipticity.</p>","PeriodicalId":732,"journal":{"name":"Physics of Wave Phenomena","volume":"32 3","pages":"227 - 231"},"PeriodicalIF":1.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical Study of the Influence of the Medium Acidity on the Interaction between Gold Nanoparticles and Bovine Serum Albumin in Aqueous Solution","authors":"E. A. Molkova,&nbsp;V. I. Pustovoi,&nbsp;I. V. Baimler,&nbsp;A. V. Simakin,&nbsp;D. E. Burmistrov,&nbsp;I. V. Gorudko,&nbsp;S. V. Gudkov","doi":"10.3103/S1541308X24700213","DOIUrl":"10.3103/S1541308X24700213","url":null,"abstract":"<p>The influence of the solution acidity on the interaction between bovine serum albumin (BSA) molecules and gold nanoparticles in solutions has been investigated by absorbance spectroscopy, fluorescence spectroscopy, and dynamic light scattering (DLS). The influence of pH on the processes of aggregation–disaggregation of gold nanoparticles with BSA and without it and on the denaturation of protein solution is demonstrated. It is also shown that BSA molecules can stabilize gold nanoparticles at acidic pH values of 2.0–4.0. The data obtained can be useful for physiologists studying the influence of nanoparticles on different biological media of the body.</p>","PeriodicalId":732,"journal":{"name":"Physics of Wave Phenomena","volume":"32 3","pages":"232 - 240"},"PeriodicalIF":1.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural Mechanisms of Transitions between Ices with Different Densities—Features of Water Phase Diagrams","authors":"E. A. Zheligovskaya,&nbsp;G. A. Lyakhov","doi":"10.3103/S1541308X24700183","DOIUrl":"10.3103/S1541308X24700183","url":null,"abstract":"<p>Structural mechanisms are developed for transitions between ices with either high or low density. Fractions of hydrogen bonds retained in the course of the transitions are calculated. Relative degrees of space filling by molecules of the considered ices are estimated. An assumption is formulated and partially substantiated that boundary exists between ice phases in the low-temperature region of the <i>PvT</i> phase diagram of ices. A new method for construction of <i>PvTb</i> diagrams of water is justified using the results of the structural analysis. The hydrogen bond concentration <i>b</i> serves as the second order parameter of phase transitions.</p>","PeriodicalId":732,"journal":{"name":"Physics of Wave Phenomena","volume":"32 3","pages":"209 - 219"},"PeriodicalIF":1.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of Self-Assembly of Water Nanostructures","authors":"M. V. Kirov","doi":"10.3103/S1541308X24700158","DOIUrl":"10.3103/S1541308X24700158","url":null,"abstract":"<p>A specific feature of regular water nanostructures, as well as extended ice, is residual entropy. The number of configurations with different arrangement of hydrogen atoms (protons) is immense. Of prime interest are the most stable proton configurations. The properties of the most unfavorable configurations of water clusters and other ice-like systems are generally beyond the attention of researchers. In this paper we present the results of studying the most weakly bound proton configurations of water nanostructures. The highly unusual spontaneous structural transformations of some weakly bound configurations are enumerated. Rather unexpectedly, one of these transformations demonstrated a pronounced ability of cubic water clusters to self-organization. The results of studying the processes of self-organization of water nanostructures from these clusters are presented. Similar behavior of the simplest system of cubic water clusters and very complex biopolymers is indicated; this similarity covers the high-level self-organization, specific type of molecular asymmetry, self-assembly of one-dimensional aperiodic crystals, and the letter code.</p>","PeriodicalId":732,"journal":{"name":"Physics of Wave Phenomena","volume":"32 3","pages":"190 - 195"},"PeriodicalIF":1.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Natural Submicron Heterogeneities in Aqueous Solutions of ATP","authors":"N. V. Penkov,&nbsp;N. A. Penkova,&nbsp;V. A. Zhmurin,&nbsp;A. G. Pogorelov","doi":"10.3103/S1541308X24700134","DOIUrl":"10.3103/S1541308X24700134","url":null,"abstract":"<p>Submicron heterogeneities (SMHs) spontaneously arising in aqueous solutions of adenosine triphosphate (ATP) are studied. Their size of about 100 nm is close to the size of SMHs earlier detected in other solutions. The SMHs have a ζ-potential of about –10 mV. It is one of their stability factors. It is shown that the tendency for ATP to form SMHs depends on the ionic composition. After removal of SMHs from the ATP solution by filtering they do not form for more than two hours in the presence of Ca²⁺, while when Ca²⁺ is absent or replaced with Mg²⁺, the SMHs form in less than 30 min. In some cases, fast formation of SMHs hampers their adequate investigation. Analysis of dielectric spectra of ATP solutions in the presence of Ca²⁺ before and after filering has shown that hydration of Ca·ATP complexes inside SMHs is manifested by lower binding of water molecules and smaller number of free water molecules as compared to hydration of Ca·ATP complexes not included in SMHs.</p>","PeriodicalId":732,"journal":{"name":"Physics of Wave Phenomena","volume":"32 3","pages":"178 - 186"},"PeriodicalIF":1.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation of Reactive Oxygen Species during Water Drops Fall on a Solid Surface","authors":"I. V. Baimler,&nbsp;S. V. Gudkov,&nbsp;T. A. Matveeva,&nbsp;A. V. Simakin,&nbsp;I. A. Shcherbakov","doi":"10.3103/S1541308X24700146","DOIUrl":"10.3103/S1541308X24700146","url":null,"abstract":"<p>The concentration of hydrogen peroxide and hydroxyl radicals in dependence of the intensity (strength) of water drop impact on a solid surface has been measured. The intensity was varied by changing the fall height from 1 to 4 m and the tilt angle of the surface onto which drops fell. It is shown that the content of hydrogen peroxide and hydroxyl radicals in solution increases after the drop impact on the solid surface. Apparently, the main mechanism of the observed effects is the generation of singlet oxygen and its further reduction.</p>","PeriodicalId":732,"journal":{"name":"Physics of Wave Phenomena","volume":"32 3","pages":"187 - 189"},"PeriodicalIF":1.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of COSMO Water Models in Quantum Quasi-Docking","authors":"D. C. Kutov,&nbsp;A. V. Sulimov,&nbsp;V. B. Sulimov","doi":"10.3103/S1541308X2470016X","DOIUrl":"10.3103/S1541308X2470016X","url":null,"abstract":"<p>Two solvent models, COSMO (old parametrization) and COSMO2 (new parametrization) are compared for a set of protein–ligand complexes in quantum quasi-docking, which is two-stage docking: positioning of a ligand in a target protein and calculation of binding enthalpy of the protein–ligand system using the PM7 quantum-chemical semiempirical method. In quantum quasi-docking, a wide spectrum of unique low-energy minima of the protein–ligand system is first found while employing the classical force field. Then energies of all these minima are recalculated within one of the continual models using the modern PM7 method with allowance for the solvent, and the global energy minimum is determined among the recalculated energies. The solution of the quantum quasi-docking problem is the position of the ligand in the protein corresponding to the global minimum of the protein–ligand system energy calculated by the quantum-chemical method with allowance for the solvent. Effectiveness of quantum quasi-docking is defined by the value (below 2 Å) of the root-mean-square deviation of ligand atoms from one another in two positions, namely, the position of the ligand in the protein corresponding to the calculated global energy minimum and the experimentally found crystallized position of the ligand with the protein. Comparison is performed for ten protein–ligand test complexes with well-defined structures taken from the Protein Data Bank, for which the ligand–protein binding enthalpy is measured and the positioning of the ligand in the protein is successful in quasi-docking within both solvent models used. In both methods, PM7 + COSMO and PM7 + COSMO2, a high correlation coefficient of the experimental and calculated ligand–protein binding enthalpy is obtained for both calculation techniques. Allowance for moveability of protein atoms in calculations of binding enthalpy leads to an increase in its negative values and to a slight decrease in the correlation coefficient of the experimental and calculated values. The role of hydrogen bonds between protein and ligand atoms is revealed: their contribution to binding enthalpy ranges from 14 to 24% for different complexes. The results indicate the way of implementing quantum docking so that the global minimum of the protein–ligand system energy calculated by the quantum-chemical technique is immediately obtained using the global optimization procedure.</p>","PeriodicalId":732,"journal":{"name":"Physics of Wave Phenomena","volume":"32 3","pages":"196 - 202"},"PeriodicalIF":1.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}