A. Chaikovsky, M. Korol, A. Malinka, E. Zege, I. Katsev, A. Prikhach, S. Denisov, V. Dick, P. Goloub, L. Blarel, L. Chaikovskaya, A. Lapyonok, T. Podvin, N. Denishchik-Nelubina, A. Fedarenka, V. Svidinsky
The paper presents lecture materials given at the Nineteenth International Conference and School on Quantum Electronics “Laser Physics and Applications” (19th ICSQE) in 2016, Sozopol, Bulgaria and contains the results of the 10-year research of Belarusian Antarctic expeditions to study the atmospheric aerosol and Earth surface in Antarctica. The works focus on the studying variability and trends of aerosol, cloud and snow characteristics in the Antarctic and the links of these processes with the long range transport of atmospheric pollutants and climate changes.
{"title":"Combined ground-based and satellite remote sensing of atmospheric aerosol and Earth surface in the Antarctic","authors":"A. Chaikovsky, M. Korol, A. Malinka, E. Zege, I. Katsev, A. Prikhach, S. Denisov, V. Dick, P. Goloub, L. Blarel, L. Chaikovskaya, A. Lapyonok, T. Podvin, N. Denishchik-Nelubina, A. Fedarenka, V. Svidinsky","doi":"10.1117/12.2261794","DOIUrl":"https://doi.org/10.1117/12.2261794","url":null,"abstract":"The paper presents lecture materials given at the Nineteenth International Conference and School on Quantum Electronics “Laser Physics and Applications” (19th ICSQE) in 2016, Sozopol, Bulgaria and contains the results of the 10-year research of Belarusian Antarctic expeditions to study the atmospheric aerosol and Earth surface in Antarctica. The works focus on the studying variability and trends of aerosol, cloud and snow characteristics in the Antarctic and the links of these processes with the long range transport of atmospheric pollutants and climate changes.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123704414","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. Dakova, A. Dakova, V. Slavchev, P. Staykov, L. Kovachev
In last two decades the phenomena resulting from the evolution of ultra-short laser pulses in nonlinear dispersive medium actively are being studied. The most commonly used equation for describing the dynamics of optical pulses in one-dimensional and planar waveguides is the standard nonlinear Schrodinger equation (NSE). It works very well for nanosecond and picosecond laser pulses, but in the frames of femtosecond optics, it is necessary two additional terms to be included. They are responsible for higher order of linear dispersion and dispersion of nonlinearity. These effects are significant in the range of ultra-short light pulses. In the present paper, it is presented a theoretical model of the propagation of optical solitons. We found an exact analytical soliton solution of the modified NSE, including third order of linear dispersion and dispersion of nonlinearity. It is possible to observe a soliton as a result of the dynamic balance between effects of higher order of dispersion and nonlinearity.
{"title":"Soliton propagation in isotropic media under the influence of third order of linear dispersion and dispersion of nonlinearity","authors":"D. Dakova, A. Dakova, V. Slavchev, P. Staykov, L. Kovachev","doi":"10.1117/12.2263442","DOIUrl":"https://doi.org/10.1117/12.2263442","url":null,"abstract":"In last two decades the phenomena resulting from the evolution of ultra-short laser pulses in nonlinear dispersive medium actively are being studied. The most commonly used equation for describing the dynamics of optical pulses in one-dimensional and planar waveguides is the standard nonlinear Schrodinger equation (NSE). It works very well for nanosecond and picosecond laser pulses, but in the frames of femtosecond optics, it is necessary two additional terms to be included. They are responsible for higher order of linear dispersion and dispersion of nonlinearity. These effects are significant in the range of ultra-short light pulses. In the present paper, it is presented a theoretical model of the propagation of optical solitons. We found an exact analytical soliton solution of the modified NSE, including third order of linear dispersion and dispersion of nonlinearity. It is possible to observe a soliton as a result of the dynamic balance between effects of higher order of dispersion and nonlinearity.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125218449","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}
This paper reviews recent progresses in ultrafast laser-based X-ray sources and their potential applications to high throughput X-ray imaging. Prospects for the utilization of X-rays sources related to the Laser Wakefield electron Acceleration (LWFA) are more specifically discussed with emphasis on application in diagnostic radiology.
{"title":"The ultrafast high-peak power lasers in future biomedical and medical x-ray imaging","authors":"J. Kieffer, S. Fourmaux, A. Król","doi":"10.1117/12.2261795","DOIUrl":"https://doi.org/10.1117/12.2261795","url":null,"abstract":"This paper reviews recent progresses in ultrafast laser-based X-ray sources and their potential applications to high throughput X-ray imaging. Prospects for the utilization of X-rays sources related to the Laser Wakefield electron Acceleration (LWFA) are more specifically discussed with emphasis on application in diagnostic radiology.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"229 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116437877","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 present experimental and theoretical investigation of the first picoseconds of formation of white continuum from 100 fs laser pulse in 0.5 cm BK7 glass. The theory gives an answer to the question of the physical mechanism of asymmetrical ultra-broadening of the pulses in the initial moment of filamentation. The spectra obtained from the experiment are compared with the spectrum profiles of the physical model and are in very good coincidence.
本文对100fs激光脉冲在0.5 cm BK7玻璃中形成白色连续体的第一皮秒进行了实验和理论研究。该理论给出了在成丝初始时刻脉冲不对称超展宽的物理机制的答案。将实验所得的光谱与物理模型的光谱曲线进行了比较，两者吻合良好。
{"title":"Avalanche parametric conversion in the initial moment of filamentation","authors":"D. Georgieva, L. Kovachev, N. Nedyalkov","doi":"10.1117/12.2263483","DOIUrl":"https://doi.org/10.1117/12.2263483","url":null,"abstract":"We present experimental and theoretical investigation of the first picoseconds of formation of white continuum from 100 fs laser pulse in 0.5 cm BK7 glass. The theory gives an answer to the question of the physical mechanism of asymmetrical ultra-broadening of the pulses in the initial moment of filamentation. The spectra obtained from the experiment are compared with the spectrum profiles of the physical model and are in very good coincidence.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"149 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127264278","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. Todorov, V. Polischuk, A. Krasteva, S. Cartaleva, A. Sargsyan, T. Vartanyan
The fluorescence and non-linear absorption spectra of Cs133 vapour in an extremely thin cell were calculated by using the perturbation theory with respect to the pumping field intensity. The problem of the atoms’ non-linear polarization was solved for arbitrary values of the total momenta of the resonance levels pumped by a linearly-polarised laser field. It was demonstrated that the spontaneous emission from the upper level affects the amplitude and sign of the lower level longitudinal alignment and results in a change of the amplitude and sign of the non-linear absorption resonance at the closed transition. The comparison of the numerical calculations with the experimental data for the D2 line of 133Cs shows a very good agreement.
{"title":"Nonlinear resonances sign reversal and longitudinal alignment on the resonant levels of 133Cs thin-layer vapour","authors":"G. Todorov, V. Polischuk, A. Krasteva, S. Cartaleva, A. Sargsyan, T. Vartanyan","doi":"10.1117/12.2263622","DOIUrl":"https://doi.org/10.1117/12.2263622","url":null,"abstract":"The fluorescence and non-linear absorption spectra of Cs133 vapour in an extremely thin cell were calculated by using the perturbation theory with respect to the pumping field intensity. The problem of the atoms’ non-linear polarization was solved for arbitrary values of the total momenta of the resonance levels pumped by a linearly-polarised laser field. It was demonstrated that the spontaneous emission from the upper level affects the amplitude and sign of the lower level longitudinal alignment and results in a change of the amplitude and sign of the non-linear absorption resonance at the closed transition. The comparison of the numerical calculations with the experimental data for the D2 line of 133Cs shows a very good agreement.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134538990","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. Stoykova, D. Nazarova, N. Berberova, A. Gotchev, B. Ivanov, G. Mateev
Dynamic laser speckle analysis is non-destructive detection of physical or biological activity through statistical processing of speckle patterns on the surface of diffusely reflecting objects. This method is sensitive to microscopic changes of the surface over time and needs simple optical means. Advances in computers and 2D optical sensors forced development of pointwise algorithms. They rely on acquisition of a temporal sequence of correlated speckle images and generate activity data as a 2D spatial contour map of the estimate of a given statistical parameter. The most widely used pointwise estimates are the intensity-based estimates which compose each map entry from a time sequence of intensity values taken at one and the same pixel in the acquired speckle images. Accuracy of the pointwise approach is strongly affected by the signal-dependent nature of the speckle data when the spread of intensity fluctuations depends on the intensity itself. The latter leads to erroneous activity determination at non-uniform distribution of intensity in the laser beam for the non-normalized estimates. Normalization of the estimates, introduces errors. We propose to apply binarization to the acquired speckle images by comparing the intensity values in the temporal sequence for a given spatial point to the mean intensity value estimated for this point and to evaluate a polar correlation function. Efficiency of this new processing algorithm is checked both by simulation and experiment.
{"title":"Dynamic laser speckle metrology with binarization of speckle patterns","authors":"E. Stoykova, D. Nazarova, N. Berberova, A. Gotchev, B. Ivanov, G. Mateev","doi":"10.1117/12.2262330","DOIUrl":"https://doi.org/10.1117/12.2262330","url":null,"abstract":"Dynamic laser speckle analysis is non-destructive detection of physical or biological activity through statistical processing of speckle patterns on the surface of diffusely reflecting objects. This method is sensitive to microscopic changes of the surface over time and needs simple optical means. Advances in computers and 2D optical sensors forced development of pointwise algorithms. They rely on acquisition of a temporal sequence of correlated speckle images and generate activity data as a 2D spatial contour map of the estimate of a given statistical parameter. The most widely used pointwise estimates are the intensity-based estimates which compose each map entry from a time sequence of intensity values taken at one and the same pixel in the acquired speckle images. Accuracy of the pointwise approach is strongly affected by the signal-dependent nature of the speckle data when the spread of intensity fluctuations depends on the intensity itself. The latter leads to erroneous activity determination at non-uniform distribution of intensity in the laser beam for the non-normalized estimates. Normalization of the estimates, introduces errors. We propose to apply binarization to the acquired speckle images by comparing the intensity values in the temporal sequence for a given spatial point to the mean intensity value estimated for this point and to evaluate a polar correlation function. Efficiency of this new processing algorithm is checked both by simulation and experiment.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"10226 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131046238","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 paper presents our results on the study of the efficiency of inter-fractional changes in hemoglobin molecules depending on the laser radiation parameters. The evaluation of the quantum efficiency of light interaction in vivo with oxyhemoglobin (HbO2) and carboxyhemoglobin (HbCO) in the blood at wavelengths for 525 and 605 nm is presented. The photodissociation yield of 11% for HbO2 and 79% for HbCO are measured at the wavelength of 525 nm and 10 % for HbO2 and 76 % for HbCO at a wavelength of 605 nm. Thus, the quantum yield of photodissociation of the HbCO is considerably higher, which ensures high efficiency of photodecomposition of the HbCO in the blood. The obtained results can be used in the clinical phototherapy practice for effective treatment of CO poisoning.
{"title":"Estimation of the quantum efficiency of the photodissociation of HbO2 and HbCO","authors":"A. Gisbrecht, S. Mamilov, S. S. Esman, M. Asimov","doi":"10.1117/12.2261829","DOIUrl":"https://doi.org/10.1117/12.2261829","url":null,"abstract":"The paper presents our results on the study of the efficiency of inter-fractional changes in hemoglobin molecules depending on the laser radiation parameters. The evaluation of the quantum efficiency of light interaction in vivo with oxyhemoglobin (HbO2) and carboxyhemoglobin (HbCO) in the blood at wavelengths for 525 and 605 nm is presented. The photodissociation yield of 11% for HbO2 and 79% for HbCO are measured at the wavelength of 525 nm and 10 % for HbO2 and 76 % for HbCO at a wavelength of 605 nm. Thus, the quantum yield of photodissociation of the HbCO is considerably higher, which ensures high efficiency of photodecomposition of the HbCO in the blood. The obtained results can be used in the clinical phototherapy practice for effective treatment of CO poisoning.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131354186","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 this paper we have demonstrated coherent population trapping and Rydberg state excitation in the five level media. We have analysed the influence of non zero multiphoton detunings and the self-phase modulation on these processes.
{"title":"Coherent population trapping in five-level system","authors":"E. Gazazyan","doi":"10.1117/12.2258620","DOIUrl":"https://doi.org/10.1117/12.2258620","url":null,"abstract":"In this paper we have demonstrated coherent population trapping and Rydberg state excitation in the five level media. We have analysed the influence of non zero multiphoton detunings and the self-phase modulation on these processes.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127115528","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. Zekou, I. Tsilikas, E. Chatzitheodoridis, A. Serafetinides
Conservation of cultural heritage treasures is the most important issue for transferring knowledge to the public through the next generation of students, academics, and researchers. Although this century is authenticating e-books and information by means of electronic text, still historical manuscripts as content as well as objects are the main original recourses of keeping a record of this transformation. The current work focuses on cleaning paper samples by the application of pulsed light, which is interventional. Experiments carried out using paper samples that are artificially colonized with Ulocladium chartarum. Paper is treated by Nd:YAG laser light. The available wavelength is 1064 nm, at various fluences, repetition rates and number of pulses. Two types of paper are stained with fungi colonies, which grow on substrates of clean paper, as well as on paper with ink text. The first type of paper is Whatman No.1056, which is closer to pure cellulose. The second type of paper is a page of a cultural heritage book published in 1926. Cleaning is performed using laser irradiation, thus defining the damage threshold of each sample. The treatment on paper Watman showed a yellowing, especially on areas with high concentration of fungi. The second sample was more durable to the exposure, performing the best results at higher fluences. Eventually, the paper samples are characterized, with optical microscopy and SEM/EDX analyses, prior to and after cleaning.
{"title":"Laser paper cleaning: the method of cleaning historical books","authors":"E. Zekou, I. Tsilikas, E. Chatzitheodoridis, A. Serafetinides","doi":"10.1117/12.2262426","DOIUrl":"https://doi.org/10.1117/12.2262426","url":null,"abstract":"Conservation of cultural heritage treasures is the most important issue for transferring knowledge to the public through the next generation of students, academics, and researchers. Although this century is authenticating e-books and information by means of electronic text, still historical manuscripts as content as well as objects are the main original recourses of keeping a record of this transformation. The current work focuses on cleaning paper samples by the application of pulsed light, which is interventional. Experiments carried out using paper samples that are artificially colonized with Ulocladium chartarum. Paper is treated by Nd:YAG laser light. The available wavelength is 1064 nm, at various fluences, repetition rates and number of pulses. Two types of paper are stained with fungi colonies, which grow on substrates of clean paper, as well as on paper with ink text. The first type of paper is Whatman No.1056, which is closer to pure cellulose. The second type of paper is a page of a cultural heritage book published in 1926. Cleaning is performed using laser irradiation, thus defining the damage threshold of each sample. The treatment on paper Watman showed a yellowing, especially on areas with high concentration of fungi. The second sample was more durable to the exposure, performing the best results at higher fluences. Eventually, the paper samples are characterized, with optical microscopy and SEM/EDX analyses, prior to and after cleaning.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"194 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122838585","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}
High intensity energy fluxes, such as electron beams and laser beams are widely used for surface alloying of metals and alloys. These technologies are able to cause the formation of the so called melt pool where the alloying elements interact each other. It is known that the homogenization of the surface alloy can be explained by intense Marangoni convection, caused by the high temperature gradient in the melt pool. The convection is inversely to the speed of the specimen motion during the alloying process and therefore, the choice of low alloying velocity will reflect on more homogeneous structure of the obtained alloy. In this study, a comparison of the structure and properties of electron and laser beam surface alloying of aluminium with niobium was conducted. The phase composition of the alloyed layers was determined by XRD (X-ray diffraction) with CuKα radiation. The microstructure was studied by SEM (Scanning Electron Microscopy). Chemical analysis was carried out using an EDX electron probe microanalyser. The microhardness of the obtained samples is also measured and compared with respect to the technology of the formation of each surface alloy.
{"title":"Comparative study of electron and laser beam surface alloying","authors":"S. Valkov, P. Petrov, R. Lazarova","doi":"10.1117/12.2262352","DOIUrl":"https://doi.org/10.1117/12.2262352","url":null,"abstract":"High intensity energy fluxes, such as electron beams and laser beams are widely used for surface alloying of metals and alloys. These technologies are able to cause the formation of the so called melt pool where the alloying elements interact each other. It is known that the homogenization of the surface alloy can be explained by intense Marangoni convection, caused by the high temperature gradient in the melt pool. The convection is inversely to the speed of the specimen motion during the alloying process and therefore, the choice of low alloying velocity will reflect on more homogeneous structure of the obtained alloy. In this study, a comparison of the structure and properties of electron and laser beam surface alloying of aluminium with niobium was conducted. The phase composition of the alloyed layers was determined by XRD (X-ray diffraction) with CuKα radiation. The microstructure was studied by SEM (Scanning Electron Microscopy). Chemical analysis was carried out using an EDX electron probe microanalyser. The microhardness of the obtained samples is also measured and compared with respect to the technology of the formation of each surface alloy.","PeriodicalId":355156,"journal":{"name":"International School on Quantum Electronics: Laser Physics and Applications","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128203940","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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