A Saturable Absorber based on thin and dense Cs2 + Rb2 + K2 molecular vapor mixture has been investigated. It is revealed that relaxation time of photobleaching effect in dense Cs2 + Rb2 + K2 is decreased with the mixture density and achieves 280 ps. It is demonstrated experimentally that a train of 3 - 5 pulses with the pulse duration of approximately 300 ps is generated as a result of passive Q-switching of YAG:Nd3+ laser. Such experiments are possible to perform due to development of unique sapphire cell containing the mixture of molecular vapor. There are several advantages of the mixture usage as a Saturable Absorber for passive Q-switching of solid state lasers.
{"title":"Broadband ultrafast saturable absorber based on thin and dense alkaline molecular vapors","authors":"D. Sarkisyan, A. Sarkisyan","doi":"10.1117/12.375278","DOIUrl":"https://doi.org/10.1117/12.375278","url":null,"abstract":"A Saturable Absorber based on thin and dense Cs2 + Rb2 + K2 molecular vapor mixture has been investigated. It is revealed that relaxation time of photobleaching effect in dense Cs2 + Rb2 + K2 is decreased with the mixture density and achieves 280 ps. It is demonstrated experimentally that a train of 3 - 5 pulses with the pulse duration of approximately 300 ps is generated as a result of passive Q-switching of YAG:Nd3+ laser. Such experiments are possible to perform due to development of unique sapphire cell containing the mixture of molecular vapor. There are several advantages of the mixture usage as a Saturable Absorber for passive Q-switching of solid state lasers.","PeriodicalId":427427,"journal":{"name":"Atomic and Molecular Spectroscopy","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127510044","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 mechanism, explaining amplification of scintillations in mixed aluminates activated by cerium ions - (Y1-xLux)AlO3:Ce (0
提出了一种解释铈离子- (Y1-xLux)AlO3:Ce (0
{"title":"Amplification of scintillations in mixed crystals","authors":"A. Maloyan, É. G. Sharoyan","doi":"10.1117/12.375282","DOIUrl":"https://doi.org/10.1117/12.375282","url":null,"abstract":"A mechanism, explaining amplification of scintillations in mixed aluminates activated by cerium ions - (Y1-xLux)AlO3:Ce (0 <EQ x <EQ 1) is proposed. Quasichemical reactions of ions Ce3+ and Ce4+ with holes and electrons causing scintillations are considered. Is shown, that the intensity of scintillations increases with decrease of mean free paths of electrons and holes and that it is proportional to the parameter of the compositional disorder x (1-x). Also the mechanism of amplification of scintillations caused by transfer of excitation energy by excitons is considered.","PeriodicalId":427427,"journal":{"name":"Atomic and Molecular Spectroscopy","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123192019","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 observe the forming of modulation pulses, by registration the optical pulses modulated in the time by photomultiplier which works in a photons count (PC) regime. The separate PC pulses are registered in the case of low light intensity. Pulse of modulation is formed if the intensity increases. It is shown, that the minimal registrative duration of the pulse is determined by one photo-electron (OPE) pulse. It imposes limitation on the possibility of signal registration. In the space language, it leads to minimal possible size of the picture spot, which is limited by the size of photosensitive grain of photoplate. The resolution of both a optical communication on a long distances or by the registration of supershort pulses will be limited also by the duration of OPE pulses.
{"title":"Spatio-temporal analogy in an experiment on photon counting","authors":"V. B. Pakhalov","doi":"10.1117/12.375299","DOIUrl":"https://doi.org/10.1117/12.375299","url":null,"abstract":"We observe the forming of modulation pulses, by registration the optical pulses modulated in the time by photomultiplier which works in a photons count (PC) regime. The separate PC pulses are registered in the case of low light intensity. Pulse of modulation is formed if the intensity increases. It is shown, that the minimal registrative duration of the pulse is determined by one photo-electron (OPE) pulse. It imposes limitation on the possibility of signal registration. In the space language, it leads to minimal possible size of the picture spot, which is limited by the size of photosensitive grain of photoplate. The resolution of both a optical communication on a long distances or by the registration of supershort pulses will be limited also by the duration of OPE pulses.","PeriodicalId":427427,"journal":{"name":"Atomic and Molecular Spectroscopy","volume":"1981 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130322465","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. M. Petrosyan, R. Hovsepyan, E. Kokanyan, R. Feigelson
Based on the lithium vacancy defect structure model of non- stoichiometric lithium niobate, a correlation was found between the OH absorption band and dopant charge. In addition, the threshold concentration for suppressing the photorefractive effect in Sc doped lithium niobate was evaluated using phase-matching temperature measurements. It was also shown that hafnium can suppress the photorefractive effect. A criterion for searching for new nonphotorefractive dopants has been formulated. New possible candidates are suggested and crystals of some of them have been grown.
{"title":"Growth and evaluation of lithium niobate crystals containing nonphotorefractive dopants","authors":"A. M. Petrosyan, R. Hovsepyan, E. Kokanyan, R. Feigelson","doi":"10.1117/12.375280","DOIUrl":"https://doi.org/10.1117/12.375280","url":null,"abstract":"Based on the lithium vacancy defect structure model of non- stoichiometric lithium niobate, a correlation was found between the OH absorption band and dopant charge. In addition, the threshold concentration for suppressing the photorefractive effect in Sc doped lithium niobate was evaluated using phase-matching temperature measurements. It was also shown that hafnium can suppress the photorefractive effect. A criterion for searching for new nonphotorefractive dopants has been formulated. New possible candidates are suggested and crystals of some of them have been grown.","PeriodicalId":427427,"journal":{"name":"Atomic and Molecular Spectroscopy","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122439422","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}
Supercritical CO2 can induce crystallization of amorphous polymers. Molecular level insight into the microstructures of CO2-processed polymers is needed to form a basis for utilization and optimization of supercritical fluid processing of polymeric materials. Spectroscopy is an economic tool to probe interactions at a molecular level. This understanding will help engineers to utilize molecular level information for improving macroscopic properties of polymeric materials by supercritical fluid processing. FT-IR spectroscopy has been applied to elucidate the morphology and microstructure of polymers processed with supercritical CO2. FTIR spectra of syndiotactic polystyrene show an increased degree of crystallinity after being subjected to scCO2. The various crystalline forms induced by CO2 in syndiotactic polystyrene were characterized via FTIR spectra. FTIR spectroscopy has been also used to measure the kinetics of CO2-induced crystallization in these polymers.
{"title":"In-situ spectroscopy of polymers processed with supercritical carbon dioxide","authors":"S. Kazarian, C. Lawrence, B. Briscoe","doi":"10.1117/12.375295","DOIUrl":"https://doi.org/10.1117/12.375295","url":null,"abstract":"Supercritical CO2 can induce crystallization of amorphous polymers. Molecular level insight into the microstructures of CO2-processed polymers is needed to form a basis for utilization and optimization of supercritical fluid processing of polymeric materials. Spectroscopy is an economic tool to probe interactions at a molecular level. This understanding will help engineers to utilize molecular level information for improving macroscopic properties of polymeric materials by supercritical fluid processing. FT-IR spectroscopy has been applied to elucidate the morphology and microstructure of polymers processed with supercritical CO2. FTIR spectra of syndiotactic polystyrene show an increased degree of crystallinity after being subjected to scCO2. The various crystalline forms induced by CO2 in syndiotactic polystyrene were characterized via FTIR spectra. FTIR spectroscopy has been also used to measure the kinetics of CO2-induced crystallization in these polymers.","PeriodicalId":427427,"journal":{"name":"Atomic and Molecular Spectroscopy","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126232078","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 Faraday effect in potassium vapor pumped by nanosecond pulses of near resonant laser radiation is studied experimentally. The input radiation with linewidth 3 cm-1 had a central frequency vp equals 13055 cm-1 which was 12 cm-1 higher than 4S1/2 - 4P3/2 atomic transition frequency v0 equals 13043 cm-1. The strong spectral broadening of pump radiation allowed to observe the Faraday rotation at frequencies v+/- 1 equals v0 +/- 2.5 cm-1 located closer to the atomic resonance where the rotation was high. The decrease of Faraday rotation from 150 degree(s) to 20 degree(s) with the increase of the intensity of pump radiation from 2 (DOT) 105 to 107 W/cm2 has been measured. The saturation of 4S1/2 - 4P3/2 transition is considered as a cause of suppression of Faraday rotation. The contributions of one photon resonance absorption, as well as of multiphoton processes, caused by more intense off resonant part of the broadened pump radiation (having frequency detuning 12 cm-1), to saturation of resonant transition is discussed. The experimental results are compared with theoretical calculations performed.
{"title":"Influence of radiation intensity on resonant Faraday rotation in potassium vapor","authors":"R. Drampyan, M. Movsessian","doi":"10.1117/12.375287","DOIUrl":"https://doi.org/10.1117/12.375287","url":null,"abstract":"The Faraday effect in potassium vapor pumped by nanosecond pulses of near resonant laser radiation is studied experimentally. The input radiation with linewidth 3 cm-1 had a central frequency vp equals 13055 cm-1 which was 12 cm-1 higher than 4S1/2 - 4P3/2 atomic transition frequency v0 equals 13043 cm-1. The strong spectral broadening of pump radiation allowed to observe the Faraday rotation at frequencies v+/- 1 equals v0 +/- 2.5 cm-1 located closer to the atomic resonance where the rotation was high. The decrease of Faraday rotation from 150 degree(s) to 20 degree(s) with the increase of the intensity of pump radiation from 2 (DOT) 105 to 107 W/cm2 has been measured. The saturation of 4S1/2 - 4P3/2 transition is considered as a cause of suppression of Faraday rotation. The contributions of one photon resonance absorption, as well as of multiphoton processes, caused by more intense off resonant part of the broadened pump radiation (having frequency detuning 12 cm-1), to saturation of resonant transition is discussed. The experimental results are compared with theoretical calculations performed.","PeriodicalId":427427,"journal":{"name":"Atomic and Molecular Spectroscopy","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134538650","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 short description of the project CHROMOS, a space astrophysical observatory, consisting by three telescopes- spectrographs and one telescope-astrograph, all with working angle of 5 degree in diameter and wavelength region 2000 - 3000 angstroms. The optical schemes of all four telescopes are presented together with their optical and geometrical parameters.
{"title":"Chromos: space astrophysical observatory","authors":"G. A. Gurzadyan","doi":"10.1117/12.375289","DOIUrl":"https://doi.org/10.1117/12.375289","url":null,"abstract":"A short description of the project CHROMOS, a space astrophysical observatory, consisting by three telescopes- spectrographs and one telescope-astrograph, all with working angle of 5 degree in diameter and wavelength region 2000 - 3000 angstroms. The optical schemes of all four telescopes are presented together with their optical and geometrical parameters.","PeriodicalId":427427,"journal":{"name":"Atomic and Molecular Spectroscopy","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122654123","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 investigate the conquest of sideband laser cooling and heating due to weak broad-band noise for a harmonically trapped two-level ion. The two opposite processes from an equilibrium distribution in the ion's quantum state of motion, i.e., the ground state of motion is depopulated. As another consequence we find population inversion between different manifolds of the ion's combined quantum states of internal electronic structure and external motion. This effect only results from the quantized treatment of the ion's motion.
{"title":"Population inversion for a single trapped two-level ion","authors":"G. Kryuchkyan, B. Kneer","doi":"10.1117/12.375302","DOIUrl":"https://doi.org/10.1117/12.375302","url":null,"abstract":"We investigate the conquest of sideband laser cooling and heating due to weak broad-band noise for a harmonically trapped two-level ion. The two opposite processes from an equilibrium distribution in the ion's quantum state of motion, i.e., the ground state of motion is depopulated. As another consequence we find population inversion between different manifolds of the ion's combined quantum states of internal electronic structure and external motion. This effect only results from the quantized treatment of the ion's motion.","PeriodicalId":427427,"journal":{"name":"Atomic and Molecular Spectroscopy","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122895477","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}
R. Hovsepyan, E. Kafadaryan, E. Vardanyan, S. Grigoryan, R. Vardanyan, A. L. Manukyan
Monocrystalline c-axis oriented thin films of PbTiO3 with various hole concentration were prepared by Cu doping with 0.1, 0.5, 1.0 mas.% and substituting Zr for Ti (Zr:Ti equals 52:48). We report concentration-dependent far- and mid- infrared reflectivity spectra of these compounds focusing on the electronic properties. Optical functions (ε 1, ε 2, σ , -Im ε -1) have been analyzed by Kramers-Kronig transformation to reflectivity spectra measured in a frequency range of 200 - 10000 cm-1 at room temperature. Conductivity spectra show a complete semiconducting dependence that can be analyzed by Drude-Lorentz model and in the terms of dynamic interaction, which leads to a frequency dependent scattering rate and enhanced low-frequency carrier mass 0.5 mas.% Cu in PbTiO3 decreases effective mass from 3.5 to 1.5 near 200 cm-1 and increases relaxation time as compared with the undoped sample.
采用0.1、0.5、1.0 mas Cu掺杂制备了不同空穴浓度的PbTiO3单晶c轴取向薄膜。用Zr代替Ti (Zr:Ti = 52:48)。我们报告了这些化合物的浓度依赖的远红外和中红外反射率光谱，重点是电子性质。用Kramers-Kronig变换分析了室温下200 ~ 10000 cm-1频率范围内的光学函数ε 1、ε 2、σ、- im ε -1的反射率。电导率谱表现出完全的半导体依赖性，可以用德鲁德-洛伦兹模型和动态相互作用来分析，这导致了频率依赖性散射率和低频载流子质量提高0.5 mas。与未掺杂的样品相比，含Cu的PbTiO3在200 cm-1附近的有效质量从3.5降低到1.5，弛豫时间增加。
{"title":"Infrared reflectivity study of Cu-doped PbTiO3 and PbZr0.52 Ti0.48O3 ferroelectric thin films","authors":"R. Hovsepyan, E. Kafadaryan, E. Vardanyan, S. Grigoryan, R. Vardanyan, A. L. Manukyan","doi":"10.1117/12.375286","DOIUrl":"https://doi.org/10.1117/12.375286","url":null,"abstract":"Monocrystalline c-axis oriented thin films of PbTiO3 with various hole concentration were prepared by Cu doping with 0.1, 0.5, 1.0 mas.% and substituting Zr for Ti (Zr:Ti equals 52:48). We report concentration-dependent far- and mid- infrared reflectivity spectra of these compounds focusing on the electronic properties. Optical functions (ε 1, ε 2, σ , -Im ε -1) have been analyzed by Kramers-Kronig transformation to reflectivity spectra measured in a frequency range of 200 - 10000 cm-1 at room temperature. Conductivity spectra show a complete semiconducting dependence that can be analyzed by Drude-Lorentz model and in the terms of dynamic interaction, which leads to a frequency dependent scattering rate and enhanced low-frequency carrier mass 0.5 mas.% Cu in PbTiO3 decreases effective mass from 3.5 to 1.5 near 200 cm-1 and increases relaxation time as compared with the undoped sample.","PeriodicalId":427427,"journal":{"name":"Atomic and Molecular Spectroscopy","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121603987","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 highly efficient cascade tripling of 1.32 micrometers Nd:YAG laser emission using combination of LiIO3 and KTP crystals. The generation of 0.44 micrometers radiation in KTP has been shown to occur at the purely noncritical phase-matching condition at slightly elevated temperature. Conversion efficiency of third harmonic generation in relation to second harmonic energy was approximately 60% in 4 mm long KTP crystal. The temperature and angular characteristics of conversion are presented.
{"title":"Highly efficient third harmonic generation of 1.32-μm radiation of a Nd:YAG laser in KTP","authors":"G. Damazyan, T. Sanamyan","doi":"10.1117/12.375297","DOIUrl":"https://doi.org/10.1117/12.375297","url":null,"abstract":"We report highly efficient cascade tripling of 1.32 micrometers Nd:YAG laser emission using combination of LiIO3 and KTP crystals. The generation of 0.44 micrometers radiation in KTP has been shown to occur at the purely noncritical phase-matching condition at slightly elevated temperature. Conversion efficiency of third harmonic generation in relation to second harmonic energy was approximately 60% in 4 mm long KTP crystal. The temperature and angular characteristics of conversion are presented.","PeriodicalId":427427,"journal":{"name":"Atomic and Molecular Spectroscopy","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126558647","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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