Vadim Semashko - Academia.edu (original) (raw)
Papers by Vadim Semashko
EPJ Web of Conferences, 2017
Here we report on laser ablation approach to produce dielectric crystalline nanoparticles Ce:LiYF... more Here we report on laser ablation approach to produce dielectric crystalline nanoparticles Ce:LiYF4 inspired by method for metal nanoparticles fabrication in aqueous solutions. The obtained water solution has shown tangible presence of compound we believe to be agglomerates of Ce:LiYF4 nanocrystals. The obtained powder has shown luminescence with peaks at 310 nm and 325 nm which is characteristic for the scheelite structured fluoride and luminescence decay quenching characteristic for Cedoped nanoparticles.
Ultraviolet short-pulse generation and amplification in new tunable laser medium (Ce/sup 3+/:LuLiF/s
Technical Digest. CLEO/Pacific Rim'95. The Pacific Rim Conference on Lasers and Electro-Optics
ABSTRACT Not Available
EPJ Web of Conferences, 2017
Luminescence decay properties of crystalline LaF3 nanoparticles containing 12 % of Ce 3+ ions col... more Luminescence decay properties of crystalline LaF3 nanoparticles containing 12 % of Ce 3+ ions collected at different stages of microwave hydrothermal treatment were studied. The microwave treatment has led to improvement of surface perturbed sites luminescence together with reducing PL decay time of regular sites apparently due to higher surface/volume ratio.
Ce,Pr:LiY1-xLuxF4 mixed crystals as perspective active media for UV lasing
2018 International Conference Laser Optics (ICLO), 2018
We demonstrated good prospects of using crystals Ce<sup>3+</sup>, Pr<sup>3+<... more We demonstrated good prospects of using crystals Ce<sup>3+</sup>, Pr<sup>3+</sup>:LiY<inf>1-x</inf>Lu<inf>x</inf>F<inf>4</inf> as an active medium of solid-state UV laser with up-conversion pumping.
Ce3+:LuLiF4 as an Excimer-Laser-Pumped Ultraviolet Tunable Solid-State Amplifier
Advanced Solid State Lasers, 2004
Ce3+:LuLiF, as an Excimer-Laser-Pumped Ultraviolet Tunable Solid-State Amplifier ... Nobuhiko Sar... more Ce3+:LuLiF, as an Excimer-Laser-Pumped Ultraviolet Tunable Solid-State Amplifier ... Nobuhiko Sarukura, Zhenlin Liu, and Yusaburo Segawa Photodynamics Research Center, The Institute of Physical and Chemical Research (RIKEN), Nagamachi, Koeji 19-1399, Aoba-ku, ...
Modified Dye-Doped Polymer Active Media with Advanced Laser Damage Resistance and Photochemical Stability
Advanced Solid State Lasers, 1993
The role of photochemical transformations of tetrahydrobiopterin in the pathogenesis and phototherapy of vitiligo
XIV International Conference on Pulsed Lasers and Laser Applications, 2019
Melanogenesis disorder leads to several pathologies, including vitiligo. Tetrahydrobiopterin (H4B... more Melanogenesis disorder leads to several pathologies, including vitiligo. Tetrahydrobiopterin (H4Bip) as the phenylalanine 4-hydroxylase coenzyme catalyzes the oxidation of phenylalanine to tyrosine (a melanin precursor). H4Bip is easily oxidized by oxygen in vivo and in vitro. Vitiligo is accompanied by three-fivefold increased de-novo synthesis of H4Bip, its excess and its further oxidation are essential factors in the pathogenesis of vitiligo. We have demonstrated that pterin products of H4Bip autoxidation (dihydropterin (H2Ptr), dihydroxanthopterin and pterin) predominate over biopterin products (dihydrobiopterin (H2Bip) and biopterin). It was shown that ultraviolet (UV) irradiation accelerates the autoxidation while the products of oxidative degradation of H4Bip act as photosensitizers. Photosensitized oxidation of H4Bip can contribute to the pathogenesis of vitiligo. The main distinguishing feature of UV photooxidation of H4Bip from autoxidation was the formation of dihydropterin (Н2Ptr)2 and dihydrobiopterin (Н2Bip)2 dimers. Here we reported on the dependences of the photodimerization reaction on the wavelength and intensity of radiation using xenon lamps and UV tunable lasers as sources of UV radiation. It was shown that UV irradiation with a laser is more efficient than that with xenon lamp. It was established that the greatest number of dimers were formed by irradiating the H4Bip solution by radiation with a wavelength in the range 308-312 nm. The data obtained are discussed in the context of UVB narrowband vitiligo phototherapy.
Ultraviolet picosecond pulses from an all-solid-state Ce:LiSAF master oscillator and Ce:LiCAF power amplifier system
Advanced Solid State Lasers, 1996
290-nm, 590-psec, 300-µJ pulses are generated from a compact Ce:LiSAF/Ce:LiCAF master oscillator ... more 290-nm, 590-psec, 300-µJ pulses are generated from a compact Ce:LiSAF/Ce:LiCAF master oscillator and power amplifier system pumped by the fourth harmonic of a conventional Nd:YAG laser. Ultraviolet picosecond pulses from an all-solid-state Ce:LiSAF/Ce:LiCAF master oscillator and power amplifier system.
Towards the Understanding of the Physically-Limited Operation of LiCAF:Ce Tunable Solid-State Laser
Advanced Solid State Lasers, 2004
Laser-like effects and upconversion fluorescence temporal dynamic in Tm3+, Yb3+doped YF3single crystals
Journal of Physics: Conference Series, 2014
ABSTRACT A new way of managing fluorescence features in doped bulk and nanosized materials by var... more ABSTRACT A new way of managing fluorescence features in doped bulk and nanosized materials by variation of excitation temporal characteristics is demonstrated. Random laser-like effect on 3H4-3F4 transitions of Tm3+ ions in Yb,Tm:YF3 single crystal was revealed under rectangular pulse train excitation in 930-980 spectral domain.
非晶質Ta_2O_5半導電層における表面プロフィルの勾配はナノスケール電流安定性を調節する【Powered by NICT】
Applied Surface Science, 2017
Ultraviolet Picosecond-Pulse Amplification in a New Solid-State-Laser Medium: Ce3+:LuLiF4
Photodynamic processes in Ce + Yb:CaF2 crystals investigation
Here the photochemical properties of CaF2 crystal doped by Ce3+ and Yb3+ ions under pumping with ... more Here the photochemical properties of CaF2 crystal doped by Ce3+ and Yb3+ ions under pumping with ultraviolet (UV) irradiation resonant to the Ce3+ ion interconfigurational 5d-4f transitions were studied and significant codoping effect on the crystal solarization suppression was observed. The photodynamic processes model occurring in the active medium and which taking into account the color center formation and processes of enhanced free charges recombination via valence change of variety of impurity centers was proposed. This model allows to explain both electronic and hole types color centers suppression in Ce:CaF2 sampels codoped by Yb3+ ions. It was shown that Yb3+ ions in the crystal act as centers of electron and hole recombination with probability dependent on the extra charge compensation type. Therefore the proposed antisolarant mechanism of the coactivation effect satisfactorily describes photochemical properties of fluorite and other crystal hosts.
14-mJ, 1-nsec, 289-nm pulses from an all-solid-state Ce:LiCAF master oscillator and power amplifier system
Advanced Solid State Lasers, 1997
... Vadim V. SEMASHKO, Alexander K. NAUMOV, Stella L. KORABLEVA, and Ravil Yu. ... OSA TOPS Vol. ... more ... Vadim V. SEMASHKO, Alexander K. NAUMOV, Stella L. KORABLEVA, and Ravil Yu. ... OSA TOPS Vol. 10 Advanced Solid State Lasers, 1997 Clifford R. Pollock and Walter R. Bosenberg (ed.) 81997 Optical Society ofAmerica 24 Page 2. Advanced Solid State Lasers 25 5 - ...
Ce3+: LiBaF3 as New Prospective Active Material for Tunable UV Laser with Direct UV Pumping
Advanced Solid State Lasers, 1997
ABSTRACT © 1997 Optical Society of America
Optical Materials, 2020
Thermal lens, absorption coefficient for 1076 nm radiation and spectral dependence of the Verdet ... more Thermal lens, absorption coefficient for 1076 nm radiation and spectral dependence of the Verdet constant were measured in PrF 3 , EuF 2.11 and Na 0.38 Ho 0.62 F 2.24 crystals for magneto-optical applications. As evaluated in the 400-1310 nm wavelength range, the Verdet constant of the EuF 2.11 crystals is ~30% higher than that of the TGG crystals, an at the wavelength of 1557 nm it is 100% higher. The Verdet constant of PrF 3 crystals is ~5% lower than in TGG throughout the studied wavelength range. Na 0.38 Ho 0.62 F 2.24 crystals have the lowest (among the studied crystals) value of the Verdet constant that is 50-80% lower than in TGG. The thermal lens was measured by the phase-shift interferometry technique and has the sign opposite to that of the TGG lens for all considered crystal. The thermo-optical constant P and the dependence of the thermal lens on the absorbed power were calculated. It is shown that the optical power of thermal lens in PrF 3 , EuF 2.11 and Na 0.38 Ho 0.62 F 2.24 at equal absorbed laser power is, respectively, 1.3, 1.7 and 1.8 times higher than in TGG.
Ceramics International, 2020
New effective luminescence thermometers based on novel host Ba 4 Y 3 F 17 doped with Pr 3+ and Pr... more New effective luminescence thermometers based on novel host Ba 4 Y 3 F 17 doped with Pr 3+ and Pr 3+ /Yb 3+ in 80-320 K temperature range were studied. The absolute temperature sensitivity (S a) of both Ba 4 Y 3 F 17 : Pr 3+ (0.1 mol %) and Ba 4 Y 3 F 17 : Pr 3+ (0.1 mol.%): Yb 3+ (10.0 mol.%)nanothermometers based on luminescence intensity ratio (LIR) between two Pr 3+ emission bands (3 P 1-3 H 5 and 3 P 0-3 H 5) demonstrate a notable value (0.011 K −1 at 300 K) in the 200-320 K range. The Ba 4 Y 3 F 17 : Pr 3+ (0.1 mol.%): Yb 3+ (10.0 mol.%)nanothermometers based on LIR between 3 P 0 → 3 H 4 of Pr 3+ and 2 F 5/2 → 2 F 7/2 of Yb 3+ emission bands demonstrate high S a into the 80-200 K range with maximal S a = 0,0778 K −1 at 100 K. The stability of the phosphors was revealed by thermo-cycling experiments.
Nanosystems: Physics, Chemistry, Mathematics, 2018
We have synthesized single-phase powders of Ca 1−x−y YbxPryF 2+x+y solid solutions with an averag... more We have synthesized single-phase powders of Ca 1−x−y YbxPryF 2+x+y solid solutions with an average particle size of about 35 nm by co-precipitation from aqueous nitrate solutions. After annealing at 600 • C during 1 hour, the particle size was increased up to 150-200 nm. Individual luminescence bands of praseodymium are distinguishable in the luminescence spectrum. The intensity of the luminescence of ytterbium increased by a factor of 1000 in comparison with the unannealed samples. The highest luminescence intensity of ytterbium was detected for the Ca 0.9495 Yb 0.0500 Pr 0.0005 F 2.0505 .
EPJ Web of Conferences, 2019
The experimental results of applying crystal-chemical methods aimed to improving the spectral-kin... more The experimental results of applying crystal-chemical methods aimed to improving the spectral-kinetic properties of active media based on fluoride crystals with scheelite (LiY1-xLuF4) and colquiriite (LiCa1-xAlF6) structures doped by rare-earth (Ce3+ and Pr3+) and Cr3+ ions are discussed. The energetic and spectral characteristics of lasers based on the active media are presented. The special attention is focused on the prospects of using these lasers in the task of optosensorics, biomedicine, and security systems.
EPJ Web of Conferences, 2019
The synthesis conditions and the results of spectral-kinetic studies of disordered crystals serie... more The synthesis conditions and the results of spectral-kinetic studies of disordered crystals series CaF2-LaF3-PrF3 with variable chemical composition are presented. The prospects of using these crystals as active media for the visible spectral range DPSS laser pumped by InGaN (GaN) laser diodes and operating on 4f-4f transitions of Pr3+ ions are discussed.
EPJ Web of Conferences, 2017
Here we report on laser ablation approach to produce dielectric crystalline nanoparticles Ce:LiYF... more Here we report on laser ablation approach to produce dielectric crystalline nanoparticles Ce:LiYF4 inspired by method for metal nanoparticles fabrication in aqueous solutions. The obtained water solution has shown tangible presence of compound we believe to be agglomerates of Ce:LiYF4 nanocrystals. The obtained powder has shown luminescence with peaks at 310 nm and 325 nm which is characteristic for the scheelite structured fluoride and luminescence decay quenching characteristic for Cedoped nanoparticles.
Ultraviolet short-pulse generation and amplification in new tunable laser medium (Ce/sup 3+/:LuLiF/s
Technical Digest. CLEO/Pacific Rim'95. The Pacific Rim Conference on Lasers and Electro-Optics
ABSTRACT Not Available
EPJ Web of Conferences, 2017
Luminescence decay properties of crystalline LaF3 nanoparticles containing 12 % of Ce 3+ ions col... more Luminescence decay properties of crystalline LaF3 nanoparticles containing 12 % of Ce 3+ ions collected at different stages of microwave hydrothermal treatment were studied. The microwave treatment has led to improvement of surface perturbed sites luminescence together with reducing PL decay time of regular sites apparently due to higher surface/volume ratio.
Ce,Pr:LiY1-xLuxF4 mixed crystals as perspective active media for UV lasing
2018 International Conference Laser Optics (ICLO), 2018
We demonstrated good prospects of using crystals Ce<sup>3+</sup>, Pr<sup>3+<... more We demonstrated good prospects of using crystals Ce<sup>3+</sup>, Pr<sup>3+</sup>:LiY<inf>1-x</inf>Lu<inf>x</inf>F<inf>4</inf> as an active medium of solid-state UV laser with up-conversion pumping.
Ce3+:LuLiF4 as an Excimer-Laser-Pumped Ultraviolet Tunable Solid-State Amplifier
Advanced Solid State Lasers, 2004
Ce3+:LuLiF, as an Excimer-Laser-Pumped Ultraviolet Tunable Solid-State Amplifier ... Nobuhiko Sar... more Ce3+:LuLiF, as an Excimer-Laser-Pumped Ultraviolet Tunable Solid-State Amplifier ... Nobuhiko Sarukura, Zhenlin Liu, and Yusaburo Segawa Photodynamics Research Center, The Institute of Physical and Chemical Research (RIKEN), Nagamachi, Koeji 19-1399, Aoba-ku, ...
Modified Dye-Doped Polymer Active Media with Advanced Laser Damage Resistance and Photochemical Stability
Advanced Solid State Lasers, 1993
The role of photochemical transformations of tetrahydrobiopterin in the pathogenesis and phototherapy of vitiligo
XIV International Conference on Pulsed Lasers and Laser Applications, 2019
Melanogenesis disorder leads to several pathologies, including vitiligo. Tetrahydrobiopterin (H4B... more Melanogenesis disorder leads to several pathologies, including vitiligo. Tetrahydrobiopterin (H4Bip) as the phenylalanine 4-hydroxylase coenzyme catalyzes the oxidation of phenylalanine to tyrosine (a melanin precursor). H4Bip is easily oxidized by oxygen in vivo and in vitro. Vitiligo is accompanied by three-fivefold increased de-novo synthesis of H4Bip, its excess and its further oxidation are essential factors in the pathogenesis of vitiligo. We have demonstrated that pterin products of H4Bip autoxidation (dihydropterin (H2Ptr), dihydroxanthopterin and pterin) predominate over biopterin products (dihydrobiopterin (H2Bip) and biopterin). It was shown that ultraviolet (UV) irradiation accelerates the autoxidation while the products of oxidative degradation of H4Bip act as photosensitizers. Photosensitized oxidation of H4Bip can contribute to the pathogenesis of vitiligo. The main distinguishing feature of UV photooxidation of H4Bip from autoxidation was the formation of dihydropterin (Н2Ptr)2 and dihydrobiopterin (Н2Bip)2 dimers. Here we reported on the dependences of the photodimerization reaction on the wavelength and intensity of radiation using xenon lamps and UV tunable lasers as sources of UV radiation. It was shown that UV irradiation with a laser is more efficient than that with xenon lamp. It was established that the greatest number of dimers were formed by irradiating the H4Bip solution by radiation with a wavelength in the range 308-312 nm. The data obtained are discussed in the context of UVB narrowband vitiligo phototherapy.
Ultraviolet picosecond pulses from an all-solid-state Ce:LiSAF master oscillator and Ce:LiCAF power amplifier system
Advanced Solid State Lasers, 1996
290-nm, 590-psec, 300-µJ pulses are generated from a compact Ce:LiSAF/Ce:LiCAF master oscillator ... more 290-nm, 590-psec, 300-µJ pulses are generated from a compact Ce:LiSAF/Ce:LiCAF master oscillator and power amplifier system pumped by the fourth harmonic of a conventional Nd:YAG laser. Ultraviolet picosecond pulses from an all-solid-state Ce:LiSAF/Ce:LiCAF master oscillator and power amplifier system.
Towards the Understanding of the Physically-Limited Operation of LiCAF:Ce Tunable Solid-State Laser
Advanced Solid State Lasers, 2004
Laser-like effects and upconversion fluorescence temporal dynamic in Tm3+, Yb3+doped YF3single crystals
Journal of Physics: Conference Series, 2014
ABSTRACT A new way of managing fluorescence features in doped bulk and nanosized materials by var... more ABSTRACT A new way of managing fluorescence features in doped bulk and nanosized materials by variation of excitation temporal characteristics is demonstrated. Random laser-like effect on 3H4-3F4 transitions of Tm3+ ions in Yb,Tm:YF3 single crystal was revealed under rectangular pulse train excitation in 930-980 spectral domain.
非晶質Ta_2O_5半導電層における表面プロフィルの勾配はナノスケール電流安定性を調節する【Powered by NICT】
Applied Surface Science, 2017
Ultraviolet Picosecond-Pulse Amplification in a New Solid-State-Laser Medium: Ce3+:LuLiF4
Photodynamic processes in Ce + Yb:CaF2 crystals investigation
Here the photochemical properties of CaF2 crystal doped by Ce3+ and Yb3+ ions under pumping with ... more Here the photochemical properties of CaF2 crystal doped by Ce3+ and Yb3+ ions under pumping with ultraviolet (UV) irradiation resonant to the Ce3+ ion interconfigurational 5d-4f transitions were studied and significant codoping effect on the crystal solarization suppression was observed. The photodynamic processes model occurring in the active medium and which taking into account the color center formation and processes of enhanced free charges recombination via valence change of variety of impurity centers was proposed. This model allows to explain both electronic and hole types color centers suppression in Ce:CaF2 sampels codoped by Yb3+ ions. It was shown that Yb3+ ions in the crystal act as centers of electron and hole recombination with probability dependent on the extra charge compensation type. Therefore the proposed antisolarant mechanism of the coactivation effect satisfactorily describes photochemical properties of fluorite and other crystal hosts.
14-mJ, 1-nsec, 289-nm pulses from an all-solid-state Ce:LiCAF master oscillator and power amplifier system
Advanced Solid State Lasers, 1997
... Vadim V. SEMASHKO, Alexander K. NAUMOV, Stella L. KORABLEVA, and Ravil Yu. ... OSA TOPS Vol. ... more ... Vadim V. SEMASHKO, Alexander K. NAUMOV, Stella L. KORABLEVA, and Ravil Yu. ... OSA TOPS Vol. 10 Advanced Solid State Lasers, 1997 Clifford R. Pollock and Walter R. Bosenberg (ed.) 81997 Optical Society ofAmerica 24 Page 2. Advanced Solid State Lasers 25 5 - ...
Ce3+: LiBaF3 as New Prospective Active Material for Tunable UV Laser with Direct UV Pumping
Advanced Solid State Lasers, 1997
ABSTRACT © 1997 Optical Society of America
Optical Materials, 2020
Thermal lens, absorption coefficient for 1076 nm radiation and spectral dependence of the Verdet ... more Thermal lens, absorption coefficient for 1076 nm radiation and spectral dependence of the Verdet constant were measured in PrF 3 , EuF 2.11 and Na 0.38 Ho 0.62 F 2.24 crystals for magneto-optical applications. As evaluated in the 400-1310 nm wavelength range, the Verdet constant of the EuF 2.11 crystals is ~30% higher than that of the TGG crystals, an at the wavelength of 1557 nm it is 100% higher. The Verdet constant of PrF 3 crystals is ~5% lower than in TGG throughout the studied wavelength range. Na 0.38 Ho 0.62 F 2.24 crystals have the lowest (among the studied crystals) value of the Verdet constant that is 50-80% lower than in TGG. The thermal lens was measured by the phase-shift interferometry technique and has the sign opposite to that of the TGG lens for all considered crystal. The thermo-optical constant P and the dependence of the thermal lens on the absorbed power were calculated. It is shown that the optical power of thermal lens in PrF 3 , EuF 2.11 and Na 0.38 Ho 0.62 F 2.24 at equal absorbed laser power is, respectively, 1.3, 1.7 and 1.8 times higher than in TGG.
Ceramics International, 2020
New effective luminescence thermometers based on novel host Ba 4 Y 3 F 17 doped with Pr 3+ and Pr... more New effective luminescence thermometers based on novel host Ba 4 Y 3 F 17 doped with Pr 3+ and Pr 3+ /Yb 3+ in 80-320 K temperature range were studied. The absolute temperature sensitivity (S a) of both Ba 4 Y 3 F 17 : Pr 3+ (0.1 mol %) and Ba 4 Y 3 F 17 : Pr 3+ (0.1 mol.%): Yb 3+ (10.0 mol.%)nanothermometers based on luminescence intensity ratio (LIR) between two Pr 3+ emission bands (3 P 1-3 H 5 and 3 P 0-3 H 5) demonstrate a notable value (0.011 K −1 at 300 K) in the 200-320 K range. The Ba 4 Y 3 F 17 : Pr 3+ (0.1 mol.%): Yb 3+ (10.0 mol.%)nanothermometers based on LIR between 3 P 0 → 3 H 4 of Pr 3+ and 2 F 5/2 → 2 F 7/2 of Yb 3+ emission bands demonstrate high S a into the 80-200 K range with maximal S a = 0,0778 K −1 at 100 K. The stability of the phosphors was revealed by thermo-cycling experiments.
Nanosystems: Physics, Chemistry, Mathematics, 2018
We have synthesized single-phase powders of Ca 1−x−y YbxPryF 2+x+y solid solutions with an averag... more We have synthesized single-phase powders of Ca 1−x−y YbxPryF 2+x+y solid solutions with an average particle size of about 35 nm by co-precipitation from aqueous nitrate solutions. After annealing at 600 • C during 1 hour, the particle size was increased up to 150-200 nm. Individual luminescence bands of praseodymium are distinguishable in the luminescence spectrum. The intensity of the luminescence of ytterbium increased by a factor of 1000 in comparison with the unannealed samples. The highest luminescence intensity of ytterbium was detected for the Ca 0.9495 Yb 0.0500 Pr 0.0005 F 2.0505 .
EPJ Web of Conferences, 2019
The experimental results of applying crystal-chemical methods aimed to improving the spectral-kin... more The experimental results of applying crystal-chemical methods aimed to improving the spectral-kinetic properties of active media based on fluoride crystals with scheelite (LiY1-xLuF4) and colquiriite (LiCa1-xAlF6) structures doped by rare-earth (Ce3+ and Pr3+) and Cr3+ ions are discussed. The energetic and spectral characteristics of lasers based on the active media are presented. The special attention is focused on the prospects of using these lasers in the task of optosensorics, biomedicine, and security systems.
EPJ Web of Conferences, 2019
The synthesis conditions and the results of spectral-kinetic studies of disordered crystals serie... more The synthesis conditions and the results of spectral-kinetic studies of disordered crystals series CaF2-LaF3-PrF3 with variable chemical composition are presented. The prospects of using these crystals as active media for the visible spectral range DPSS laser pumped by InGaN (GaN) laser diodes and operating on 4f-4f transitions of Pr3+ ions are discussed.