{"title":"The Effect of Inertial Backscattering in a He–Ne Ring Laser at a Wavelength of 632.8 nm","authors":"E. A. Petrukhin, A. S. Bessonov","doi":"10.3103/S1068335625602109","DOIUrl":"10.3103/S1068335625602109","url":null,"abstract":"<p>The effect is investigated of backscattering of the diffraction grating produced on the mirror surface by gas discharge UV radiation and by counterpropagating waves of a ring laser. Measurements of the dynamics of complex coupling coefficients as the ring laser slowly approaches the lock-in threshold are presented. It is shown that, when the ring laser is near the lock-in threshold, there is a slight decrease in the dissipative component of complex coupling coefficients and a significant increase in their conservative component. The physical model of these effects is discussed.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":"52 3 supplement","pages":"S261 - S273"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142242","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}
A. P. Bogatov, A. E. Drakin, N. V. D’yachkov, G. T. Mikaelyan
{"title":"Nonuniform Distribution of Gain along the Cavity Axis and Lasing Efficiency in a Diode Laser","authors":"A. P. Bogatov, A. E. Drakin, N. V. D’yachkov, G. T. Mikaelyan","doi":"10.3103/S1068335625602122","DOIUrl":"10.3103/S1068335625602122","url":null,"abstract":"<p>Use is made of the analytical solution of the wave equation to simulate the light–current characteristics of Fabry–Perot diode lasers designed to operate at high powers. It is shown that at a high output power level, the presence of axial gain nonuniformity does not lead to deviations from the linearity of this characteristic. Only near the lasing threshold, a decrease in efficiency with pump current is found, associated with the transition from a uniform axial gain distribution to a self-consistent nonuniform distribution. It is found that with significant axial nonuniformity of the electron density that depends on the power level, the total optical length of the cavity remains constant.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":"52 3 supplement","pages":"S227 - S237"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142195","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":"Scattering of a Relativistic Laser Pulse by a Dense Small-Size Plasma","authors":"A. A. Andreev, K. Yu. Platonov, M. V. Sedov","doi":"10.3103/S1068335625602110","DOIUrl":"10.3103/S1068335625602110","url":null,"abstract":"<p>We consider the interaction of a short, relativistically intense laser pulse with (sub)micron dense plasma bunches of various shapes. The electromagnetic field scattered by such targets is shown to consist of a sequence of ultrashort, tightly focused attosecond pulses. The spatial characteristics and temporal duration of such pulses are estimated and numerically calculated as functions of the parameters of the target and the laser pulse.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":"52 3 supplement","pages":"S327 - S339"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142239","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":"Second Harmonic Generation in the Interaction of a Dipole Electromagnetic Pulse with a Constant Magnetic Field","authors":"R. M. Feshchenko","doi":"10.3103/S1068335625602158","DOIUrl":"10.3103/S1068335625602158","url":null,"abstract":"<p>We discuss the generation of nonlinear harmonics by an intense dipole electromagnetic pulse in a vacuum in the presence of a constant magnetic field. Using Maxwell’s nonlinear equations, following from the Heisenberg–Euler Lagrangian in the one-loop approximation, expressions are derived for the electromagnetic field of the second harmonic generated in this case. It is shown that the second harmonic pulse in its spatial structure is a magnetic octupole pulse if the initial electromagnetic pulse is an electric- or magnetic-dipole pulse.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":"52 3 supplement","pages":"S308 - S312"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142243","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":"Calculation of Spectral and Angular Characteristics of Nonlinear Compton Scattering of a Laser Pulse","authors":"M. P. Malakhov, A. M. Fedotov","doi":"10.3103/S1068335625602146","DOIUrl":"10.3103/S1068335625602146","url":null,"abstract":"<p>We report an investigation of the process of Compton scattering of a plane-wave laser pulse on an electron in the nonlinear regime in the head-on collision geometry. Use is made of the generalized Filon method to calculate numerically the rapidly oscillating integrals that determine the matrix element of the process in the Furry representation. The behavior of the spectral-angular, angular, and spectral distributions of a scattered photon is analyzed as a function of the laser pulse amplitude, duration, polarization, and envelope shape. A new analytical expression for the backscattering spectrum is obtained for a special envelope shape of a circularly polarized pulse.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":"52 3 supplement","pages":"S291 - S307"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142240","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}
D. K. Derimedved’, N. R. Lebedev, P. A. Mikhalev, V. I. Yusupov, E. I. Mareev, N. V. Minaev
{"title":"Microstructuring of Piezoelectric Polyvinylidene Fluoride Films Using Pulsed Laser Radiation","authors":"D. K. Derimedved’, N. R. Lebedev, P. A. Mikhalev, V. I. Yusupov, E. I. Mareev, N. V. Minaev","doi":"10.3103/S106833562560216X","DOIUrl":"10.3103/S106833562560216X","url":null,"abstract":"<p>We study the methods for modifying and microstructuring polyvinylidene fluoride (PVDF) films using nanosecond and femtosecond laser pulses in order to form functional microstructures on the surface and in the near-surface layer. It is shown that microstructuring by femtosecond pulses makes it possible to ensure high resolution and minimal thermal impact on the material. The advantage of using nanosecond radiation is the possibility of rapid microstructuring over large areas, which makes this method attractive for industrial applications, with the resolution not reaching high values. We have found regimes that allow one to form structures in the near-surface layer without damaging the film surface, as well as to produce structures with an increased content of atomic carbon. The results of Raman spectroscopy show that in the regions of strong laser action there is a significant change in the conformational composition of the films, including a decrease in ferroactive conformations and a transition to the paraelectric state, which, in turn, affects the piezoelectric properties. The proposed methods for laser modification of PVDF films can be used to develop new microsensors, which opens up new horizons in the field of application of electroactive materials in various high-tech industries.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":"52 3 supplement","pages":"S319 - S326"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142246","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}
O. I. Sokolovskaya, L. A. Golovan, N. B. Tkachenko, V. V. Yakovlev
{"title":"Raman Signal Enhancement in Suspensions Containing Submicron-Sized Particles","authors":"O. I. Sokolovskaya, L. A. Golovan, N. B. Tkachenko, V. V. Yakovlev","doi":"10.3103/S1068335625601967","DOIUrl":"10.3103/S1068335625601967","url":null,"abstract":"<p>It is shown that for an optically inhomogeneous medium, which is a suspension of submicron-sized particles in liquid, both a noticeable increase in the time of radiation interaction with the medium and growth of the Raman scattering (RS) signal are possible compared to the medium without scatterers. The optical heterodyning method was used in experiments to measure the time delay of femtosecond pulses, which reached 1 ps in suspensions of rutile microparticles in dimethyl sulfoxide (DMSO) for different scatterer volume fraction. The photon dwell time in the suspensions decreased with with scatterer volume fraction increase for scatterer volume fraction higher than 0.001. Numerical simulation results of femtosecond laser pulse scattering by Monte Carlo method are in good agreement with experimental data. The simulation indicates that the maximum possible growth of the Raman signal registered in the diffuse reflection direction under multiple light scattering is up to 7.5-fold compared to the case of scatterer absence in the medium. The Raman signal collected with a lens increased 3.5 times in a suspension of rutile particles in DMSO compared to the Raman signal for DMSO without scatterers. The simulation results of Raman process in a scattering medium agree well with the experimental results of Raman signal efficiency measurement.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":"52 3 supplement","pages":"S282 - S290"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142194","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":"Ways to Reduce Angle Random Walk of Fiber-Optic Gyroscopes","authors":"M. A. Belousov, V. Yu. Venediktov, E. V. Shalymov","doi":"10.3103/S1068335625602134","DOIUrl":"10.3103/S1068335625602134","url":null,"abstract":"<p>We report and analyze various methods for reducing the angle random walk (ARW) of fiber-optic gyroscopes. The operating principle and noise theory of a fiber-optic gyroscope are briefly considered. Main attention is paid to the most popular ways to reduce ARW: increasing the total area of the fiber coil, optimizing the phase modulation depth, and reducing and compensating for the relative intensity noise (RIN). Other ways to reduce ARW are also briefly discussed, for example, by reducing the phase modulation frequency. Experimental results of applying the described methods for reducing ARW are demonstrated using advanced work on the development of fiber-optic gyroscopes as an example.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":"52 3 supplement","pages":"S247 - S260"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142196","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":"Biopsy of Embryonic Trophectoderm Cells Using Infrared Femtosecond Laser Pulses","authors":"D. S. Sitnikov, M. A. Filatov","doi":"10.3103/S1068335625602018","DOIUrl":"10.3103/S1068335625602018","url":null,"abstract":"<p>Millisecond laser sources are now widely used in assisted reproductive technologies for the trophectoderm cell biopsy procedure at the blastocyst stage. We have investigated the effectiveness of application for this purpose of infrared femtosecond laser pulses (280 fs duration and 1028 nm radiation wavelength). The biopsy was performed using standard microsurgical assist devices—holding pipettes. Pulses with an intensity of 10 to 65 TW/cm<sup>2</sup> were shown to be able to extract cells from bioptates of different thickness.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":"52 3 supplement","pages":"S274 - S281"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142244","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}
I. V. Klepikov, E. A. Vasiliev, V. F. Lebedev, E. I. Lipatov, V. G. Vins, A. V. Koliadin
{"title":"Zonal and Sectorial Distribution of Impurities in HPHT Diamonds with NV Centers","authors":"I. V. Klepikov, E. A. Vasiliev, V. F. Lebedev, E. I. Lipatov, V. G. Vins, A. V. Koliadin","doi":"10.3103/S1068335625602080","DOIUrl":"10.3103/S1068335625602080","url":null,"abstract":"<p>A detailed analysis of spectroscopic features and of the zonal and sectorial internal structure of a multisectorial HPHT diamond sample grown in the Fe–Ni–C system is presented. The sample was irradiated by electrons with energy of 3 MeV and a dose of 1.5 × 10<sup>18</sup> electron cm<sup>–2</sup> and then annealed in vacuum at 1200°C to obtain a high concentration of nitrogen-vacancy centers. Differences are established in the concentrations and incorporation forms of nitrogen in different growth sectors and of nitrogen-vacancy defects formed as a result of the treatment. Comparison of photoluminescence (PL) spectra at excitation at 488 and 785 nm and the distribution of nitrogen defects with the results of PL visualization under radiation with wavelengths of 220, 254, and 365 nm showed that photoluminescence tomography is a very informative tool for analyzing the inhomogeneity of diamond products. The Ni impurity was localized nonuniformly, many additional PL lines in the near-IR range were registered in the zones of sector {111} with high concentration of A-defects. This feature complements the defect-impurity composition of the diamond element with a high concentration of NV centers and may adversely affect the characteristics of a promising laser material.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":"52 3 supplement","pages":"S313 - S318"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142241","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}