V. P. Dresvyanskiy, A. Kuznetsov, S. Enkhbat, O. Bukhtsooj, N. Bobina, S. Alekseev, V. Losev, E. F. Martynovich
The paper presents the results of experimental and theoretical studies of the role of avalanche ionization in the process of highly nonlinear generation of electron-hole pairs in the interaction of intense femtosecond laser radiation with dosimetric crystals LiF:Mg,Ti. We assume that the effective formation of defects of hole-interstitial type, which consist of molecular halogen ions placed in one cationic and two anionic vacancies, distinguished by high-temperature peaks in the thermally stimulated luminescence curves, is feasibly connected with avalanche ionization processes occurring in the regions of passage of light filaments. The calculated dependences of the plasma density on time during the laser pulse made with taking into account the avalanche ionization for this type of crystals show that the contribution of avalanche ionization to the electron-hole plasma density is comparable to that of the multiphoton tunneling mechanism.
{"title":"The role of avalanche ionization in generation of defects in lithium fluoride crystals under the action of femtosecond laser pulses","authors":"V. P. Dresvyanskiy, A. Kuznetsov, S. Enkhbat, O. Bukhtsooj, N. Bobina, S. Alekseev, V. Losev, E. F. Martynovich","doi":"10.1117/12.2554180","DOIUrl":"https://doi.org/10.1117/12.2554180","url":null,"abstract":"The paper presents the results of experimental and theoretical studies of the role of avalanche ionization in the process of highly nonlinear generation of electron-hole pairs in the interaction of intense femtosecond laser radiation with dosimetric crystals LiF:Mg,Ti. We assume that the effective formation of defects of hole-interstitial type, which consist of molecular halogen ions placed in one cationic and two anionic vacancies, distinguished by high-temperature peaks in the thermally stimulated luminescence curves, is feasibly connected with avalanche ionization processes occurring in the regions of passage of light filaments. The calculated dependences of the plasma density on time during the laser pulse made with taking into account the avalanche ionization for this type of crystals show that the contribution of avalanche ionization to the electron-hole plasma density is comparable to that of the multiphoton tunneling mechanism.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128336383","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}
Features of compression of large-aperture negatively chirped amplified pulses of various aperture and durations up to a few-cycle in IR spectral regions are analyzed. Using the modified ray-tracing algorithm, the spectral-angular dependences of the radiation at different points of the beam cross section at the outputs of the grating compressors constructed according to the Offner, Martinez scheme and the scheme with a single-lens internal telescope are calculated. Offner compressor scheme has minimal aberrations and introduces a spectral angular chirp with a divergence much lower than the beam diffraction divergence. It was shown that in the region of 1.4 μm, negatively chirped pulses can be compressed down to near bandwidth limited duration of ~30 fs over the entire 40 mm beam aperture. It was also shown that, using stretchers with an internal telescope based on the Offner scheme, in the region of 3.6 μm it is possible to compress amplified negatively chirped pulses with duration of 40 ps and with a spectrum width close to an octave down to near bandwidth-limited duration of 18 fs duration at a 20 mm aperture.
{"title":"Compressors of negatively chirped pulses with internal telescope","authors":"D. Shvydkoy, V. Trunov","doi":"10.1117/12.2553210","DOIUrl":"https://doi.org/10.1117/12.2553210","url":null,"abstract":"Features of compression of large-aperture negatively chirped amplified pulses of various aperture and durations up to a few-cycle in IR spectral regions are analyzed. Using the modified ray-tracing algorithm, the spectral-angular dependences of the radiation at different points of the beam cross section at the outputs of the grating compressors constructed according to the Offner, Martinez scheme and the scheme with a single-lens internal telescope are calculated. Offner compressor scheme has minimal aberrations and introduces a spectral angular chirp with a divergence much lower than the beam diffraction divergence. It was shown that in the region of 1.4 μm, negatively chirped pulses can be compressed down to near bandwidth limited duration of ~30 fs over the entire 40 mm beam aperture. It was also shown that, using stretchers with an internal telescope based on the Offner scheme, in the region of 3.6 μm it is possible to compress amplified negatively chirped pulses with duration of 40 ps and with a spectrum width close to an octave down to near bandwidth-limited duration of 18 fs duration at a 20 mm aperture.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124979282","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}
Stimulated Rayleigh–Mie scattering (SRMS) in two-photon absorption liquids is realized by a Fourier transform-limited pulsed Nd-glass laser. For the first time, we have measured anti-Stokes spectral shifts of SRMS in toluene and hexane colloids of Ag nanoparticles, as well as in pure toluene. The suspensions are prepared in the plasma discharge excited in a liquid exposed to an intense ultrasonic field above the cavitation threshold. This novel technique has been developed for the synthesis of various nano-sized materials; it provides silver nanoparticles suspensions with controlled narrow distribution of the particle size. Ultrasonic cavitation results in a drastic change in the physical properties of the liquid, providing specific conditions in the electrical discharge plasma. Ag nanoparticles with 1-2 nm radii in toluene and hexane are obtained from silver electrodes under these specific conditions and acquire unique surface characteristics which prevent them from secondary agglomeration. The values of anti-Stokes spectral shifts of SRMS appreciably exceed the Rayleigh line width in those liquids. The four-wave mixing method is applied both experimentally and theoretically to display the process as Rayleigh-induced parametric generation. We show that the amplification effect is provided predominantly by thermally induced coherent polarization oscillations, while an interference-assisted thermal grating provides formation of a self-induced optical cavity inside the interaction region.
{"title":"A comparative study of anti-Stokes shift under stimulated Rayleigh-Mie scattering in suspensions of Ag nanoparticles obtained in plasma discharge in liquid under ultrasonic cavitation","authors":"N. Bulychev, A. Erokhin, M. Kazaryan","doi":"10.1117/12.2550775","DOIUrl":"https://doi.org/10.1117/12.2550775","url":null,"abstract":"Stimulated Rayleigh–Mie scattering (SRMS) in two-photon absorption liquids is realized by a Fourier transform-limited pulsed Nd-glass laser. For the first time, we have measured anti-Stokes spectral shifts of SRMS in toluene and hexane colloids of Ag nanoparticles, as well as in pure toluene. The suspensions are prepared in the plasma discharge excited in a liquid exposed to an intense ultrasonic field above the cavitation threshold. This novel technique has been developed for the synthesis of various nano-sized materials; it provides silver nanoparticles suspensions with controlled narrow distribution of the particle size. Ultrasonic cavitation results in a drastic change in the physical properties of the liquid, providing specific conditions in the electrical discharge plasma. Ag nanoparticles with 1-2 nm radii in toluene and hexane are obtained from silver electrodes under these specific conditions and acquire unique surface characteristics which prevent them from secondary agglomeration. The values of anti-Stokes spectral shifts of SRMS appreciably exceed the Rayleigh line width in those liquids. The four-wave mixing method is applied both experimentally and theoretically to display the process as Rayleigh-induced parametric generation. We show that the amplification effect is provided predominantly by thermally induced coherent polarization oscillations, while an interference-assisted thermal grating provides formation of a self-induced optical cavity inside the interaction region.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124351197","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}
A. Karapusikov, A. Klimkin, G. Kokhanenko, A. Kuryak, K. Osipov, Y. Ponomarev, Zhang Shuo
In the report the results of experiments on the registration of IR radiation backscattering from organic aerosol are presented and discussed. The studies were conducted on the bench for prototyping lidar measurements at a controlled optical way. Water aerosol and water aerosol containing organic components like tryptophan, alcohol, glycerin, and reduced nicotinamide adenine dinucleotide (NADH) served as model media. For these experiments we have modified the experimental set up under replacing UV laser on IR one -- a tunable waveguide CO2- laser. The IR photodetector MCT cooled by liquid nitrogen was used. As a result of the study, the ability to discriminate a number of aerosols among themselves by difference of the absorption spectra under CO2- laser wavelength tuning was demonstrated. It can be used in remote sensing of the different types of organic aerosols.
{"title":"Use of longwave remote sensing for aerosol research","authors":"A. Karapusikov, A. Klimkin, G. Kokhanenko, A. Kuryak, K. Osipov, Y. Ponomarev, Zhang Shuo","doi":"10.1117/12.2554946","DOIUrl":"https://doi.org/10.1117/12.2554946","url":null,"abstract":"In the report the results of experiments on the registration of IR radiation backscattering from organic aerosol are presented and discussed. The studies were conducted on the bench for prototyping lidar measurements at a controlled optical way. Water aerosol and water aerosol containing organic components like tryptophan, alcohol, glycerin, and reduced nicotinamide adenine dinucleotide (NADH) served as model media. For these experiments we have modified the experimental set up under replacing UV laser on IR one -- a tunable waveguide CO2- laser. The IR photodetector MCT cooled by liquid nitrogen was used. As a result of the study, the ability to discriminate a number of aerosols among themselves by difference of the absorption spectra under CO2- laser wavelength tuning was demonstrated. It can be used in remote sensing of the different types of organic aerosols.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"410 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116545773","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 efficiency of a real heat engines is considered. Basing on the entropy production minimum principle it is shown that the maximum efficiency of such a machine with an optimum power is n= 1-√T2/T1 defined by the root dependence of cooler and heater temperatures. This disappointing result was obtained earlier for the optimizing the power of Carnot cycle. In this paper we derive aforementioned expression from more general conditions. And we show that it is could be applicable to describe global changes in living and nonliving nature.
{"title":"Some aspects of optimizing the power of a real heat engine","authors":"A. E. Roshdestvensky, A. Erokhin, M. Kazaryan","doi":"10.1117/12.2550619","DOIUrl":"https://doi.org/10.1117/12.2550619","url":null,"abstract":"The efficiency of a real heat engines is considered. Basing on the entropy production minimum principle it is shown that the maximum efficiency of such a machine with an optimum power is n= 1-√T2/T1 defined by the root dependence of cooler and heater temperatures. This disappointing result was obtained earlier for the optimizing the power of Carnot cycle. In this paper we derive aforementioned expression from more general conditions. And we show that it is could be applicable to describe global changes in living and nonliving nature.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131412598","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. Goncharova, Anna L. Nemoykina, Vadim O. Trufanov, S. Kulinich, V. Svetlichnyi
This paper studies the influence of photoactivation on the antibacterial activity of nanoparticles (NPs) obtained by pulsed laser ablation (PLA) of a brass target. The initial composition of the target is presented by a cubic phase is Cu65Zn35/Cu50Zn50. PLA in water was found to produce Cu2O and ZnO NPs. Generation of a different phase of brass (Cu85Zn15) was also observed. A number of studies was conducted to test the antibacterial properties of cotton treated with colloidal solution. Strain of S.aureus bacteria was used to evaluate antibacterial activity of prepared NPs, and it turned out to be high enough; an additional exposure of red light (610 nm) did not induce any changes in the antibacterial activity of the samples. Irradiation of the "soft" ultraviolet (365 nm) led to a sharp spike of the antibacterial activity an d complete death of bacteria.
{"title":"The impact of photoactivation on the antibacterial effect of nanoparticles obtained by pulsed laser ablation","authors":"D. Goncharova, Anna L. Nemoykina, Vadim O. Trufanov, S. Kulinich, V. Svetlichnyi","doi":"10.1117/12.2545864","DOIUrl":"https://doi.org/10.1117/12.2545864","url":null,"abstract":"This paper studies the influence of photoactivation on the antibacterial activity of nanoparticles (NPs) obtained by pulsed laser ablation (PLA) of a brass target. The initial composition of the target is presented by a cubic phase is Cu65Zn35/Cu50Zn50. PLA in water was found to produce Cu2O and ZnO NPs. Generation of a different phase of brass (Cu85Zn15) was also observed. A number of studies was conducted to test the antibacterial properties of cotton treated with colloidal solution. Strain of S.aureus bacteria was used to evaluate antibacterial activity of prepared NPs, and it turned out to be high enough; an additional exposure of red light (610 nm) did not induce any changes in the antibacterial activity of the samples. Irradiation of the \"soft\" ultraviolet (365 nm) led to a sharp spike of the antibacterial activity an d complete death of bacteria.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"3 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131641373","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}
G. V. Kuptsov, V. Petrov, V. Petrov, A. V. Laptev, A. Kirpichnikov, E. Pestryakov
This paper is focused on the investigation of the effect of temperature on the laser amplification process. In case of Ybdoped active media there is a significant dependency of laser and physical properties on temperature that leads to reducing of gain coefficient. Theoretical description and experimental study carried out based on Yb:YAG crystal pumped by high power laser diode. Despite the cooling of the active element, the heating significantly affects at cwpumping regime and determines the shape of gain coefficient dependency on the pump power.
{"title":"Study of the temperature effect on the laser amplification process","authors":"G. V. Kuptsov, V. Petrov, V. Petrov, A. V. Laptev, A. Kirpichnikov, E. Pestryakov","doi":"10.1117/12.2550839","DOIUrl":"https://doi.org/10.1117/12.2550839","url":null,"abstract":"This paper is focused on the investigation of the effect of temperature on the laser amplification process. In case of Ybdoped active media there is a significant dependency of laser and physical properties on temperature that leads to reducing of gain coefficient. Theoretical description and experimental study carried out based on Yb:YAG crystal pumped by high power laser diode. Despite the cooling of the active element, the heating significantly affects at cwpumping regime and determines the shape of gain coefficient dependency on the pump power.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134576143","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, P. A. Babushkin, A. Zemlyanov, A. M. Kabanov, G. Matvienko, V. Oshlakov, A. V. Petrov
The results of experimental research of the filamentation of femtosecond laser pulses using a bimorph deformable mirror, which allows controlling the position of the filamentation domain determining localization of filaments and high-intensity channels in the beam cross section. The introduction of distortions into the amplitude profile of the beam with using masks showed the inability to control the number and position of filaments in the beam cross section.
{"title":"Influence of phase and amplitude distortions of initial beam profile on the characteristics of filamentation domain","authors":"D. V. Apeksimov, P. A. Babushkin, A. Zemlyanov, A. M. Kabanov, G. Matvienko, V. Oshlakov, A. V. Petrov","doi":"10.1117/12.2554667","DOIUrl":"https://doi.org/10.1117/12.2554667","url":null,"abstract":"The results of experimental research of the filamentation of femtosecond laser pulses using a bimorph deformable mirror, which allows controlling the position of the filamentation domain determining localization of filaments and high-intensity channels in the beam cross section. The introduction of distortions into the amplitude profile of the beam with using masks showed the inability to control the number and position of filaments in the beam cross section.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133247458","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. Sosnin, E. Baksht, V. Kuznetsov, V. Panarin, D. Pechenitsin, V. Skakun, V. Tarasenko
The paper demonstrates the possibility of studying blue jets in laboratory apokamp discharges as a source of blue streamers that move upward from the discharge channel. Research data are presented on the formation of such streamers in low-pressure air at a voltage of tens of kilovolts, showing for the first time that they do arise at low (∼8 Hz) pulse repetition frequencies under pressures at which gigantic blue jets develop 10–20 km above the Earth. At a voltage of positive polarity with an amplitude of 33 kV, the streamer velocity in a pulsed apokamp discharge reaches 560 km/s. When applying microsecond voltage pulses of amplitude 15 kV with a repetition frequency of 50 kHz, the length of streamers ranges to more than 120 cm.
{"title":"Apokamp discharge as a laboratory analogue of the transient luminous events of middle atmosphere","authors":"E. Sosnin, E. Baksht, V. Kuznetsov, V. Panarin, D. Pechenitsin, V. Skakun, V. Tarasenko","doi":"10.1117/12.2541527","DOIUrl":"https://doi.org/10.1117/12.2541527","url":null,"abstract":"The paper demonstrates the possibility of studying blue jets in laboratory apokamp discharges as a source of blue streamers that move upward from the discharge channel. Research data are presented on the formation of such streamers in low-pressure air at a voltage of tens of kilovolts, showing for the first time that they do arise at low (∼8 Hz) pulse repetition frequencies under pressures at which gigantic blue jets develop 10–20 km above the Earth. At a voltage of positive polarity with an amplitude of 33 kV, the streamer velocity in a pulsed apokamp discharge reaches 560 km/s. When applying microsecond voltage pulses of amplitude 15 kV with a repetition frequency of 50 kHz, the length of streamers ranges to more than 120 cm.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122607789","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 article proposes a design of sensor of optical distortions in a wide field of view for the adaptive optical system of the Large Solar Vacuum Telescope. The calculation of the optical scheme of the sensor based on the use of two wavefront sensors was performed. The working field of view of the adaptive system with an additional sensor for determining the distortions of the wavefront is 120 arc sec. Adjusting the field of view of each Shack-Hartmann sensor up to 30 arc sec is provided by field diaphragms. It is shown that for the used second imager, the quality of subimages remains high, the standard deviation is λ /80.
{"title":"Sensor to register the optical distortions in the wide field of view of solar telescope","authors":"A. Shikhovtsev, S. Chuprakov, P. Kovadlo","doi":"10.1117/12.2553045","DOIUrl":"https://doi.org/10.1117/12.2553045","url":null,"abstract":"The article proposes a design of sensor of optical distortions in a wide field of view for the adaptive optical system of the Large Solar Vacuum Telescope. The calculation of the optical scheme of the sensor based on the use of two wavefront sensors was performed. The working field of view of the adaptive system with an additional sensor for determining the distortions of the wavefront is 120 arc sec. Adjusting the field of view of each Shack-Hartmann sensor up to 30 arc sec is provided by field diaphragms. It is shown that for the used second imager, the quality of subimages remains high, the standard deviation is λ /80.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"394 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122858502","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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