D. Lubenko, S. Alekseev, E. A. Sandabkin, V. Losev
The results of experimental studies of conditions for THz emission generation in laser filament created by focused ultrashort laser pulse of Ti: Sapphire complex are presented. The influence of magnitude and direction of applied external electric field, energy and polarization of pump radiation in one- and two-color optical schemes on the intensity, divergence, and polarization of THz radiation are investigated. THz spectra is estimated and optimal generation conditions are discussed.
{"title":"Generation of THz emission in femtosecond laser-induced filament","authors":"D. Lubenko, S. Alekseev, E. A. Sandabkin, V. Losev","doi":"10.1117/12.2613444","DOIUrl":"https://doi.org/10.1117/12.2613444","url":null,"abstract":"The results of experimental studies of conditions for THz emission generation in laser filament created by focused ultrashort laser pulse of Ti: Sapphire complex are presented. The influence of magnitude and direction of applied external electric field, energy and polarization of pump radiation in one- and two-color optical schemes on the intensity, divergence, and polarization of THz radiation are investigated. THz spectra is estimated and optimal generation conditions are discussed.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"8 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":"130973044","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}
We report on the fabrication of liquid automated filter capable of controlling the intensity of terahertz radiation in the range of 0.4-1.4 THz. The filter is a cell with a magnetic fluid (5% dispersion of 5BDSR particles in 80W-90 synthetic oil) placed on the path of THz radiation between a pair of crossed Helmholtz coils. The prototype created allows achieving an extremely high attenuation coefficient, up to 35 dB. Automatic start-up and stirring system make filter operation repeatable, even with multiple on/off filter state changes. All this allows us to speak about the operability of the presented technology and the possibility of further development of the prototype, the use of similar filters in any THz photonics systems, in which it is required to control the intensity of polarized radiation.
{"title":"Development of an automated prototype of THz filter based on magnetic fluids","authors":"E. S. Savelyev, D. Ezhov, I. Lapin, V. Cherepanov","doi":"10.1117/12.2612519","DOIUrl":"https://doi.org/10.1117/12.2612519","url":null,"abstract":"We report on the fabrication of liquid automated filter capable of controlling the intensity of terahertz radiation in the range of 0.4-1.4 THz. The filter is a cell with a magnetic fluid (5% dispersion of 5BDSR particles in 80W-90 synthetic oil) placed on the path of THz radiation between a pair of crossed Helmholtz coils. The prototype created allows achieving an extremely high attenuation coefficient, up to 35 dB. Automatic start-up and stirring system make filter operation repeatable, even with multiple on/off filter state changes. All this allows us to speak about the operability of the presented technology and the possibility of further development of the prototype, the use of similar filters in any THz photonics systems, in which it is required to control the intensity of polarized radiation.","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":"132942242","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 different commercial plastics for fused deposition modeling 3D printing are defined at room temperature in the spectral range 0.2˗1.2 THz. We compare absorption coefficients and refractive index of ABS, PETG, and SBS printed 1-4 mm plates. Different types of optical elements for controlling high-power THz radiation are studied. A comparison is made of the efficiency of attenuation of linearly polarized THz radiation with homemade band-pass polarizers obtained by etching copper from a flexible polyimide substrate. Filters and polarizers created using 3D printing or by deposition of polymer matrix with magnetic particles under external field are cost-effective and can be easily changed or replaced. Comparison between plastic insets, filters based on magnetic particles, and polyimide film filters are made.
{"title":"Prospects of controlling the propagation of high-power THz radiation by passive optical elements including 3D printed","authors":"D. Ezhov, D. Lubenko, V. Losev, Y. Andreev","doi":"10.1117/12.2614227","DOIUrl":"https://doi.org/10.1117/12.2614227","url":null,"abstract":"Optical properties of different commercial plastics for fused deposition modeling 3D printing are defined at room temperature in the spectral range 0.2˗1.2 THz. We compare absorption coefficients and refractive index of ABS, PETG, and SBS printed 1-4 mm plates. Different types of optical elements for controlling high-power THz radiation are studied. A comparison is made of the efficiency of attenuation of linearly polarized THz radiation with homemade band-pass polarizers obtained by etching copper from a flexible polyimide substrate. Filters and polarizers created using 3D printing or by deposition of polymer matrix with magnetic particles under external field are cost-effective and can be easily changed or replaced. Comparison between plastic insets, filters based on magnetic particles, and polyimide film filters are made.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"73 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":"131413297","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}
A. Zhiltsova, E. Krasnova, Alexander Prosenkov, Ana Isabel Peláez Andrés, D. Voronov, S. Patsaeva
An important characteristic of a natural reservoir is the depth distribution of the pigment composition of various groups of photosynthetic organisms and its changes in different seasons, both qualitative and quantitative. In the Arctic zone it is especially important to explore the evolution of natural water bodies under the influence of climate change and the urbanization processes in the region. This paper presents for the first time the study of bacteriochlorophyll (BChl) depth profiles derived from optical measurements accompanied by metagenomic profiling of bacterial communities in two stratified lakes, Trekhtzvetnoe and Elovoe at the Kandalaksha coast of the White Sea. Natural water with microorganisms along with hydrological measurements was sampled from various depths during expedition in March 2021. The metagenomic studies showed that biodiversity indices in both lakes did not appear to significantly diminish with depth. According to the analysis of similarity, differences between samples grouped by the lake of origin were not statistically significant. There were significant differences when samples were grouped by layer of the water column. This suggests that stratification of bacterial communities occurred according to environmental conditions in each part of the water column (oxygenated surface layer; chemocline, and anoxic bottom layers), and was not influenced by the geographical location of the lake. Differences between bacterial communities had strong correlation to changes in redox potential and light penetration, and were weakly correlated with depth and temperature; correlation with salinity and pH was not statistically significant.
{"title":"Depth distribution of optical characteristics, bacteriochlorophylls and metagenomic profiles of bacterial communities in meromictic lakes Trekhtzvetnoe and Elovoe in March 2021","authors":"A. Zhiltsova, E. Krasnova, Alexander Prosenkov, Ana Isabel Peláez Andrés, D. Voronov, S. Patsaeva","doi":"10.1117/12.2613667","DOIUrl":"https://doi.org/10.1117/12.2613667","url":null,"abstract":"An important characteristic of a natural reservoir is the depth distribution of the pigment composition of various groups of photosynthetic organisms and its changes in different seasons, both qualitative and quantitative. In the Arctic zone it is especially important to explore the evolution of natural water bodies under the influence of climate change and the urbanization processes in the region. This paper presents for the first time the study of bacteriochlorophyll (BChl) depth profiles derived from optical measurements accompanied by metagenomic profiling of bacterial communities in two stratified lakes, Trekhtzvetnoe and Elovoe at the Kandalaksha coast of the White Sea. Natural water with microorganisms along with hydrological measurements was sampled from various depths during expedition in March 2021. The metagenomic studies showed that biodiversity indices in both lakes did not appear to significantly diminish with depth. According to the analysis of similarity, differences between samples grouped by the lake of origin were not statistically significant. There were significant differences when samples were grouped by layer of the water column. This suggests that stratification of bacterial communities occurred according to environmental conditions in each part of the water column (oxygenated surface layer; chemocline, and anoxic bottom layers), and was not influenced by the geographical location of the lake. Differences between bacterial communities had strong correlation to changes in redox potential and light penetration, and were weakly correlated with depth and temperature; correlation with salinity and pH was not statistically significant.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"32 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":"130728547","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}
L. Antoshkin, A. G. Borzilov, V. Lavrinov, L. Lavrinova, A. Selin
Under the influence of atmospheric turbulence and as a result of natural vibrations of the adaptive optics system, the radiation images in the focal plane fluctuate in time relative to the laser radiation propagation axis, leading to a change in the wave front tilt angles. When accurate positioning of the focal spot is required, the elimination of angular errors becomes an important point in astronomical observations. Image stabilization on the photo detector matrix of the optical system is performed by the tilt corrector, which is one of the key elements of the software and hardware complex for emulating the tilt of the wave front.
{"title":"The image stabilization of laser radiation at the stand of the adaptive optical system","authors":"L. Antoshkin, A. G. Borzilov, V. Lavrinov, L. Lavrinova, A. Selin","doi":"10.1117/12.2606323","DOIUrl":"https://doi.org/10.1117/12.2606323","url":null,"abstract":"Under the influence of atmospheric turbulence and as a result of natural vibrations of the adaptive optics system, the radiation images in the focal plane fluctuate in time relative to the laser radiation propagation axis, leading to a change in the wave front tilt angles. When accurate positioning of the focal spot is required, the elimination of angular errors becomes an important point in astronomical observations. Image stabilization on the photo detector matrix of the optical system is performed by the tilt corrector, which is one of the key elements of the software and hardware complex for emulating the tilt of the wave front.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"64 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":"127122779","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}
Vasilii Ripenko, E. Lipatov, A. Burachenko, D. Genin, M. Shulepov
The study of exciton cathodoluminescence in diamond is not only scientific but also practical importance. Ultraviolet radiation at a wavelength of 235 nm can be used for disinfection, activation of surface reactions, photochemistry, and more. Thus, diamond is a promising material for creating a cathodoluminescent source of ultraviolet radiation. We have investigated the temperature dependences of the exciton cathodoluminescence spectra of single-crystal diamond in the temperature range from 80 to 400 K. The temperature dependences showed a characteristic increase in the intensity of exciton cathodoluminescence in the range 230-240 nm with increasing temperatures from 80 K to 150- 180 K. Further increase in temperature to room temperature (297 K) leads to a twofold decrease in the radiation intensity. With a further increase in temperature to 400 K, no change in the cathodoluminescence intensity was observed within the error
{"title":"Exciton cathodoluminescence of HTHP diamonds at elevated temperatures","authors":"Vasilii Ripenko, E. Lipatov, A. Burachenko, D. Genin, M. Shulepov","doi":"10.1117/12.2615953","DOIUrl":"https://doi.org/10.1117/12.2615953","url":null,"abstract":"The study of exciton cathodoluminescence in diamond is not only scientific but also practical importance. Ultraviolet radiation at a wavelength of 235 nm can be used for disinfection, activation of surface reactions, photochemistry, and more. Thus, diamond is a promising material for creating a cathodoluminescent source of ultraviolet radiation. We have investigated the temperature dependences of the exciton cathodoluminescence spectra of single-crystal diamond in the temperature range from 80 to 400 K. The temperature dependences showed a characteristic increase in the intensity of exciton cathodoluminescence in the range 230-240 nm with increasing temperatures from 80 K to 150- 180 K. Further increase in temperature to room temperature (297 K) leads to a twofold decrease in the radiation intensity. With a further increase in temperature to 400 K, no change in the cathodoluminescence intensity was observed within the error","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"1 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":"124357562","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}
V. Kuznetsov, E. Baksht, V. Panarin, V. Skakun, D. Sorokin, E. Sosnin
Using an electrode with a ceramic coating, a new method for the formation of an apokampic discharge in the pressure range of 30-150 Torr has been obtained. It was found that the average plasma bullets velocity propagated from such an electrode can reach 520 km/s. The results obtained are in good agreement with the simulation results obtained earlier in the framework of the streamer model.
{"title":"Peculiarities of apokamp formation from electrode with ceramic coating","authors":"V. Kuznetsov, E. Baksht, V. Panarin, V. Skakun, D. Sorokin, E. Sosnin","doi":"10.1117/12.2613627","DOIUrl":"https://doi.org/10.1117/12.2613627","url":null,"abstract":"Using an electrode with a ceramic coating, a new method for the formation of an apokampic discharge in the pressure range of 30-150 Torr has been obtained. It was found that the average plasma bullets velocity propagated from such an electrode can reach 520 km/s. The results obtained are in good agreement with the simulation results obtained earlier in the framework of the streamer model.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"14 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":"115264717","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. Karmenyan, D. Vrazhnov, E. Sandykova, E. Perevedentseva, A. Krivokharchenko, V. Nadtochenko, Chia-Liang Cheng, T. Kabanova, Tatyana E. Malakhova
The paper presents an algorithm based on low order statistics for the informative feature extraction for Raman spectroscopy data. The proposed method was tested on mouse preimplantation embryos Raman spectra. Both supervised and unsupervised machine learning methods were applied to selected the most informative features to test the separability of the processed data.
{"title":"Informative feature selection method for Raman micro-spectroscopy data","authors":"A. Karmenyan, D. Vrazhnov, E. Sandykova, E. Perevedentseva, A. Krivokharchenko, V. Nadtochenko, Chia-Liang Cheng, T. Kabanova, Tatyana E. Malakhova","doi":"10.1117/12.2613966","DOIUrl":"https://doi.org/10.1117/12.2613966","url":null,"abstract":"The paper presents an algorithm based on low order statistics for the informative feature extraction for Raman spectroscopy data. The proposed method was tested on mouse preimplantation embryos Raman spectra. Both supervised and unsupervised machine learning methods were applied to selected the most informative features to test the separability of the processed data.","PeriodicalId":205170,"journal":{"name":"Atomic and Molecular Pulsed Lasers","volume":"64 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":"115652735","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. Rogova, M. Gerasimova, F. Tomilin, E. Slyusareva
Recently, there has been an increased interest in natural polysaccharides, in particular, chitosan, which are widely used in medicine and industry. Chitosan labeled with fluorescein dyes acquires additional optical properties that can be used in sensing and delivery systems. Mechanism of binding of a polymer to a label largely determines the field of its possible applications. The quantum chemical calculation using the B3LYP/aug-cc-pVDZ theory level has been made in order to contribute to the understanding of intermolecular interactions. The geometry of fluorescein, eosin Y, and erythrosin B in the dianionic, monoanionic, and neutral quinoid forms interacting with chitosan has been optimized and the absorption spectra have been calculated using the time-dependent density functional theory taking into account the solvent. The comparison of the calculated absorption spectra with the experimental data has shown a major role of the electrostatic mechanism in binding of anionic dyes to the protonated chitosan groups.
{"title":"Quantum chemical study of the spectral characteristics of fluorescein dyes bound to chitosan","authors":"A. Rogova, M. Gerasimova, F. Tomilin, E. Slyusareva","doi":"10.1117/12.2613980","DOIUrl":"https://doi.org/10.1117/12.2613980","url":null,"abstract":"Recently, there has been an increased interest in natural polysaccharides, in particular, chitosan, which are widely used in medicine and industry. Chitosan labeled with fluorescein dyes acquires additional optical properties that can be used in sensing and delivery systems. Mechanism of binding of a polymer to a label largely determines the field of its possible applications. The quantum chemical calculation using the B3LYP/aug-cc-pVDZ theory level has been made in order to contribute to the understanding of intermolecular interactions. The geometry of fluorescein, eosin Y, and erythrosin B in the dianionic, monoanionic, and neutral quinoid forms interacting with chitosan has been optimized and the absorption spectra have been calculated using the time-dependent density functional theory taking into account the solvent. The comparison of the calculated absorption spectra with the experimental data has shown a major role of the electrostatic mechanism in binding of anionic dyes to the protonated chitosan groups.","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":"122265939","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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