The effect of the amplitude and spatial frequency of a sinusoidal wavefront over a square aperture on the far-field diffraction pattern is considered for a laser beam. An analytical solution of the Fraunhofer diffraction problem for a 2D sinusoidal wavefront over a rectangular aperture with an arbitrary integer number of periods along each side is derived using an original technique. The result coincides with high accuracy with a numerical solution obtained using the Fast Fourier Transform. It has been shown that after correcting the second-order Zernike modes by a stacked array piezoelectric deformable mirror with different numbers and patterns of control actuators, the residual wavefront aberrations may be considered approximately sinusoidal. Therefore, the results for an ideal sinusoidal wavefront could be applied to a real residual wavefront in problems of adaptive optics. For sinusoidal aberrations, the so-called beam quality β factor has been shown to increase sharply as the root-mean-square wavefront error (RMS) passes certain values. A new criterion of wavefront quality for sinusoidal and residual aberrations over a square aperture has been proposed.
{"title":"Fraunhofer diffraction and the beam quality β factor of a laser beam with sinusoidal wavefront","authors":"D. A. Yagnyatinskiy, V. Fedoseyev","doi":"10.1117/12.2614009","DOIUrl":"https://doi.org/10.1117/12.2614009","url":null,"abstract":"The effect of the amplitude and spatial frequency of a sinusoidal wavefront over a square aperture on the far-field diffraction pattern is considered for a laser beam. An analytical solution of the Fraunhofer diffraction problem for a 2D sinusoidal wavefront over a rectangular aperture with an arbitrary integer number of periods along each side is derived using an original technique. The result coincides with high accuracy with a numerical solution obtained using the Fast Fourier Transform. It has been shown that after correcting the second-order Zernike modes by a stacked array piezoelectric deformable mirror with different numbers and patterns of control actuators, the residual wavefront aberrations may be considered approximately sinusoidal. Therefore, the results for an ideal sinusoidal wavefront could be applied to a real residual wavefront in problems of adaptive optics. For sinusoidal aberrations, the so-called beam quality β factor has been shown to increase sharply as the root-mean-square wavefront error (RMS) passes certain values. A new criterion of wavefront quality for sinusoidal and residual aberrations over a square aperture has been proposed.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123129619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the modern world, it is worth seriously thinking about the quality of food consumed. Eating livestock products, we often do not think about such things as the presence of antibiotics in them. However, this can have serious consequences for the body. That is why the sanitary services of all countries pay such attention to the definition of antibiotics. Somewhere very strict standards are set on them. This article is an overview of such antibiotics as sulfaguanidine, benzylpenicillin and chloramphenicol, we also discussed the methods for the determination of antibiotics, methods of fluorescence analysis and quantum chemistry, which we will use in future studies.
{"title":"Methods for determining the residual amount of antibiotics in food","authors":"O. Tchaikovskaya, V. S. Chaydonova, M. Ashmarina","doi":"10.1117/12.2593802","DOIUrl":"https://doi.org/10.1117/12.2593802","url":null,"abstract":"In the modern world, it is worth seriously thinking about the quality of food consumed. Eating livestock products, we often do not think about such things as the presence of antibiotics in them. However, this can have serious consequences for the body. That is why the sanitary services of all countries pay such attention to the definition of antibiotics. Somewhere very strict standards are set on them. This article is an overview of such antibiotics as sulfaguanidine, benzylpenicillin and chloramphenicol, we also discussed the methods for the determination of antibiotics, methods of fluorescence analysis and quantum chemistry, which we will use in future studies.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124908993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Adamov, V. Aksenov, V. V. Dudorov, V. V. Kolosov, M. E. Levitskii
The control over beams with distributed polarization opens new ways for a wide range of applications from optical communications to laser processing of materials. This paper proposes a simple and efficient method of controlling the spatial characteristics of azimuthally polarized beams synthesized as a result of coherent combining of Gaussian beams emitted by a spatially ordered array of fiber lasers. The proposed method is based on maintaining the specified phase relations between the array subbeams by placing a phase forming element - a liquid crystal spatial light modulator - in the active feedback loop. A distinctive feature of the proposed method is the possibility of full control over beams with distributed polarization with phase control of only one component of the electric field. This leads to the significantly simpler design of the experiment. The mathematical model of beam formation and the algorithm of phase control of beams with spatially distributed polarization are discussed. The generation of beams with spatially distributed polarization, including cylindrical vector beams (CVB) and optical vortex beams (OVB), is demonstrated experimentally. The results of the experiment with an array of six fiber lasers are in a good agreement with the results of numerical simulation.
{"title":"Phase control of an azimuthally polarized beam synthesized by an array of fiber lasers","authors":"E. Adamov, V. Aksenov, V. V. Dudorov, V. V. Kolosov, M. E. Levitskii","doi":"10.1117/12.2613647","DOIUrl":"https://doi.org/10.1117/12.2613647","url":null,"abstract":"The control over beams with distributed polarization opens new ways for a wide range of applications from optical communications to laser processing of materials. This paper proposes a simple and efficient method of controlling the spatial characteristics of azimuthally polarized beams synthesized as a result of coherent combining of Gaussian beams emitted by a spatially ordered array of fiber lasers. The proposed method is based on maintaining the specified phase relations between the array subbeams by placing a phase forming element - a liquid crystal spatial light modulator - in the active feedback loop. A distinctive feature of the proposed method is the possibility of full control over beams with distributed polarization with phase control of only one component of the electric field. This leads to the significantly simpler design of the experiment. The mathematical model of beam formation and the algorithm of phase control of beams with spatially distributed polarization are discussed. The generation of beams with spatially distributed polarization, including cylindrical vector beams (CVB) and optical vortex beams (OVB), is demonstrated experimentally. The results of the experiment with an array of six fiber lasers are in a good agreement with the results of numerical simulation.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130187480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Adamov, V. Aksenov, V. V. Dudorov, V. V. Kolosov, M. E. Levitskii
The results of an experiment on formation of a scalar vortex beam in the system of coherent combining of fiber laser beams are reported. Stabilization of phase relations between optical beams is achieved by placing a helicoid phase forming diffraction optical element (DOE) made as a phase plate with helical phase profile in the active feedback loop. Time-stable vortex beams with the topological charge p = ±1 are obtained. The vortex character of the obtained beams is confirmed by the results of interferometric measurements.
{"title":"Vortex beam generation by means of control of the piston shift of a fiber array using a phase forming DOE in active feedback loop","authors":"E. Adamov, V. Aksenov, V. V. Dudorov, V. V. Kolosov, M. E. Levitskii","doi":"10.1117/12.2613693","DOIUrl":"https://doi.org/10.1117/12.2613693","url":null,"abstract":"The results of an experiment on formation of a scalar vortex beam in the system of coherent combining of fiber laser beams are reported. Stabilization of phase relations between optical beams is achieved by placing a helicoid phase forming diffraction optical element (DOE) made as a phase plate with helical phase profile in the active feedback loop. Time-stable vortex beams with the topological charge p = ±1 are obtained. The vortex character of the obtained beams is confirmed by the results of interferometric measurements.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127678416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The results of experimental and theoretical studies of behavior spectral profile of second harmonic (SH) radiation with a central wavelength of 475-477 nm during its formation in a nonlinear KDP crystal, depending on the phase matching angle and radiation intensity are presented. It is shown that a change in the propagation angle of fundamental radiation to one or the other side of phase matching angle by 16– 20 min leads to a spatially inhomogeneous broadening of the second harmonic spectrum up to two times and a shift of its maximum (averaged over the beam cross section) to shorter wavelengths from the central wavelength.
{"title":"Spectrum broadening of second harmonic femtosecond pulse in nonlinear crystal","authors":"S. Alekseev, V. Losev, V. Trunov, S. Frolov","doi":"10.1117/12.2613936","DOIUrl":"https://doi.org/10.1117/12.2613936","url":null,"abstract":"The results of experimental and theoretical studies of behavior spectral profile of second harmonic (SH) radiation with a central wavelength of 475-477 nm during its formation in a nonlinear KDP crystal, depending on the phase matching angle and radiation intensity are presented. It is shown that a change in the propagation angle of fundamental radiation to one or the other side of phase matching angle by 16– 20 min leads to a spatially inhomogeneous broadening of the second harmonic spectrum up to two times and a shift of its maximum (averaged over the beam cross section) to shorter wavelengths from the central wavelength.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125787852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. V. Apeksimov, Y. Geints, A. Zemlyanov, A. Iglakova, G. Matvienko, O. Minina, V. Oshlakov, A. V. Petrov
The evolution of the small-scale transverse structure of high-power femtosecond laser radiation propagating in air in the filamentation mode has been experimentally and theoretically studied. Experimental results were obtained using wideaperture (centimeter) collimated beams of femtosecond pulses of a titanium-sapphire laser. As a result, the features of propagation of spatially isolated high-intensity light channels, the diameter of which is several millimeters, were determined. They are formed because of Kerr self-focusing of intensity inhomogeneities in the initial transverse profile of the laser beam. It is shown that the formation of a filament (a localized light structure, the existence of which is associated with the plasma formation and the generation of conical emission) does not occur in each of these channels. The theoretical evaluation of this light channels characteristics was carried out. It is based on the diffraction-ray model of single filamentation of femtosecond laser pulses. Studying of the evolution transverse profile of a laser beam with a centimeter radius and subterawatt power along air path showed that the initial radius of intensity inhomogeneities, for which laser filamentation occur, is equal several (2.5-3.5) millimeters. The power in these inhomogeneities varies from 19 to 26 GW. Differences in the values of the radius and power of these inhomogeneities are the cause of different distances from the laser pulse source at which their self-focusing occurs.
{"title":"High-intensity light channels formed during the propagation of high-power femtosecond laser radiation in air","authors":"D. V. Apeksimov, Y. Geints, A. Zemlyanov, A. Iglakova, G. Matvienko, O. Minina, V. Oshlakov, A. V. Petrov","doi":"10.1117/12.2601905","DOIUrl":"https://doi.org/10.1117/12.2601905","url":null,"abstract":"The evolution of the small-scale transverse structure of high-power femtosecond laser radiation propagating in air in the filamentation mode has been experimentally and theoretically studied. Experimental results were obtained using wideaperture (centimeter) collimated beams of femtosecond pulses of a titanium-sapphire laser. As a result, the features of propagation of spatially isolated high-intensity light channels, the diameter of which is several millimeters, were determined. They are formed because of Kerr self-focusing of intensity inhomogeneities in the initial transverse profile of the laser beam. It is shown that the formation of a filament (a localized light structure, the existence of which is associated with the plasma formation and the generation of conical emission) does not occur in each of these channels. The theoretical evaluation of this light channels characteristics was carried out. It is based on the diffraction-ray model of single filamentation of femtosecond laser pulses. Studying of the evolution transverse profile of a laser beam with a centimeter radius and subterawatt power along air path showed that the initial radius of intensity inhomogeneities, for which laser filamentation occur, is equal several (2.5-3.5) millimeters. The power in these inhomogeneities varies from 19 to 26 GW. Differences in the values of the radius and power of these inhomogeneities are the cause of different distances from the laser pulse source at which their self-focusing occurs.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"294 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134430440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this work is to explore the effects of laser radiation on pigments based on titanium dioxide by changing its parameters. A qualitative assessment of the results of the experiments showed that laser irradiation of the pigment in solutions with concentrations from 10% to 1×10-2%, λ = 1024 nm, τ = 750 ps and an energy density of 8.7 J/cm2 leads to an increase in the turbidity of the solution and its whiter shade. Analysis of images from a microscope showed that pigment destruction is observed. Overall, the principle of destruction of the white pigment in the laboratory was proposed and the feasibility of further in vivo testing was evaluated. As a result of the research, an obtained data will serve as the foundation for the development of methods for removing white pigments for tattoos and will increase the effectiveness of permanent makeup removal.
{"title":"Optimization of laser radiation parameters for an affect on pigments, based on titanium dioxide (TiO2)","authors":"Aleksei Lichnyi, Irina Nam, Ekaterina Dikman","doi":"10.1117/12.2616446","DOIUrl":"https://doi.org/10.1117/12.2616446","url":null,"abstract":"The purpose of this work is to explore the effects of laser radiation on pigments based on titanium dioxide by changing its parameters. A qualitative assessment of the results of the experiments showed that laser irradiation of the pigment in solutions with concentrations from 10% to 1×10-2%, λ = 1024 nm, τ = 750 ps and an energy density of 8.7 J/cm2 leads to an increase in the turbidity of the solution and its whiter shade. Analysis of images from a microscope showed that pigment destruction is observed. Overall, the principle of destruction of the white pigment in the laboratory was proposed and the feasibility of further in vivo testing was evaluated. As a result of the research, an obtained data will serve as the foundation for the development of methods for removing white pigments for tattoos and will increase the effectiveness of permanent makeup removal.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126239528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical properties of single axes Li2B4O7 (LB4) crystal are defined at room temperature in the spectral range 0.03˗0.5 THz. Dispersion of the refractive index components are approximated in the form of Sellmeier equations. Dispersion properties were used to determine phase-matching conditions for THz wave generation by collinear difference frequency generation processes. To the damage threshold under the pump by train of hundreds of 60 fs pulses of Ti:sapphire laser operating at 950 nm is found to be 250 TW/cm2, as well as the coherence length and efficiency of all possible types of three wave interactions are defined.
{"title":"Detailed study on optical properties of Li2B4O7 for down-conversion to millimeter waves","authors":"D. Ezhov, N. Nikolaev, A. Mamrashev, Y. Andreev","doi":"10.1117/12.2612528","DOIUrl":"https://doi.org/10.1117/12.2612528","url":null,"abstract":"Optical properties of single axes Li2B4O7 (LB4) crystal are defined at room temperature in the spectral range 0.03˗0.5 THz. Dispersion of the refractive index components are approximated in the form of Sellmeier equations. Dispersion properties were used to determine phase-matching conditions for THz wave generation by collinear difference frequency generation processes. To the damage threshold under the pump by train of hundreds of 60 fs pulses of Ti:sapphire laser operating at 950 nm is found to be 250 TW/cm2, as well as the coherence length and efficiency of all possible types of three wave interactions are defined.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128390533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
XeCl electro-discharge laser modeling is discussed. The pump parameters of a LC-contour excitation system are studied in XeCl laser using a Ne:Xe :HCl mixture. A computation model is developed for finding the parameters of laser. The dependence of generation energy from parameters of excitation system and mixture was determined.
{"title":"Computer modeling of XeCl-lasers","authors":"S. Anufrick, A. Volodenkov, K. Znosko, V. Losev","doi":"10.1117/12.2613963","DOIUrl":"https://doi.org/10.1117/12.2613963","url":null,"abstract":"XeCl electro-discharge laser modeling is discussed. The pump parameters of a LC-contour excitation system are studied in XeCl laser using a Ne:Xe :HCl mixture. A computation model is developed for finding the parameters of laser. The dependence of generation energy from parameters of excitation system and mixture was determined.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128540840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Atomic and electronic structure of Bi2SiO5/β-Bi2O3 hetero-junction was described by means of density functional theory. The interface was found to be narrow-gap semiconductor with indirect band gap. The redistribution of states near the Fermi level in hybrid structure and the impact of spin-orbit coupling are discussed.
{"title":"Interface features and electronic structure of Bi2SiO5/β-Bi2O3 hetero-junction","authors":"E. A. Kovaleva, O. Vodyankina, V. Svetlichny","doi":"10.1117/12.2614020","DOIUrl":"https://doi.org/10.1117/12.2614020","url":null,"abstract":"Atomic and electronic structure of Bi2SiO5/β-Bi2O3 hetero-junction was described by means of density functional theory. The interface was found to be narrow-gap semiconductor with indirect band gap. The redistribution of states near the Fermi level in hybrid structure and the impact of spin-orbit coupling are discussed.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"70 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130641838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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