The growth detects in Nd:YCa4O(BO3)3(Nd:YCOB) crystals were investigated by transmission synchrotron topography.It was found that growth striations were the primary defects in Nd:YCOB crystals.Grown-in dislocations.mo...The growth detects in Nd:YCa4O(BO3)3(Nd:YCOB) crystals were investigated by transmission synchrotron topography.It was found that growth striations were the primary defects in Nd:YCOB crystals.Grown-in dislocations.mosaic blocks and inclusions were also obsered in the crystals.The effect of temperature field on the formation of growth defects in the crystals was discussed.展开更多
A self-starting mode-locked femtosecond laser is accomplished with an oxoborate self-frequency doubling crystal Yb:YCa4O(BO3)3 (Yb:YCOB) as the gain medium and a semiconductor mirror as the saturable absorber. P...A self-starting mode-locked femtosecond laser is accomplished with an oxoborate self-frequency doubling crystal Yb:YCa4O(BO3)3 (Yb:YCOB) as the gain medium and a semiconductor mirror as the saturable absorber. Pumped by a 976-nm fiber-coupled diode laser with 50-ktm core diameter, stable mode-locked laser pulses up to 430 mW were obtained at a repetition rate of 83.61 MHz under 5-W pump power. The autocorrelation measurement shows that the pulse duration is as short as 150 fs by assuming the sech2 pulse shape at a central wavelength of 1048 nm. This work has demonstrated a compact and reliable femtosecond laser source for prospective low-cost applications.展开更多
Growth and morphology of neodymium or ytterbium doped calcium gadolinium yttrium oxoborate (Re∶Ca 4Gd x Y 1- x O(BO 3) 3(Re∶GdYCOB)Re =Nd,Yb; x =0-1)were systematically studied. Polycrystalline materials used for Re...Growth and morphology of neodymium or ytterbium doped calcium gadolinium yttrium oxoborate (Re∶Ca 4Gd x Y 1- x O(BO 3) 3(Re∶GdYCOB)Re =Nd,Yb; x =0-1)were systematically studied. Polycrystalline materials used for Re∶GdYCOB single crystals growth were synthesized by multistage solid phase reaction method.Re∶GdYCOB single crystals were grown by Czochralski technique.The pulling rates are 0.5-2mm/h and the rotation rates are 10-30r/min.Usually 65-75% polycrystalline materials can be transformed into good quality single crystals under our growth conditions. The structures of some as grown Re∶GdYCOB single crystals were measured by using a four circle diffractometer.The results measured show that the space group of the crystals is C 3 s Cm.The determined lattice constants of 8 at% Nd doped Ca 4YO(BO 3) 3 single crystal are a =0.8076nm, b =1.6020nm, c =0.3527nm , β =101.23°.展开更多
End-pumped by a 976 nm diode laser,a high-repetition-rate Er:Yb:YAl3(BO3)4 microchip laser passively Q-switched by a Co2+:MgAl2 O4 crystal is reported.At a quasi-continuous-wave pump power of 20 W,a 1553 nm passively ...End-pumped by a 976 nm diode laser,a high-repetition-rate Er:Yb:YAl3(BO3)4 microchip laser passively Q-switched by a Co2+:MgAl2 O4 crystal is reported.At a quasi-continuous-wave pump power of 20 W,a 1553 nm passively Q-switched laser with the repetition rate of 544 kHz,pulse duration of 8.3 ns,and pulse energy of 3.9 μJ was obtained.To the best of our knowledge,the 544 kHz is the highest reported value for the 1.5 μm passively Q-switched pulse laser.In the continuous-wave pumping experiment,the maximum repetition rate of 144 kHz with the pulse duration of 8.0 ns and pulse energy of 1.7 μJ was obtained at the incident pump power of 6.3 W.展开更多
Novel up-conversion (UC) luminescent nano-powders, CaSc2O4:Yb3+:Er3+ were prepared with a combustion method at an ignition temperature as low as 200 oC. The CaSc2O4:Yb3+,Er3+ nano-powder had an orthorhombic C...Novel up-conversion (UC) luminescent nano-powders, CaSc2O4:Yb3+:Er3+ were prepared with a combustion method at an ignition temperature as low as 200 oC. The CaSc2O4:Yb3+,Er3+ nano-powder had an orthorhombic CaFe2O4-type structure, and showed sphere-like morphology with an average diameter of about 30 nm. It gave strong green (525, 552 nm) and red (652–674 nm) up-conversion luminescence due to the 2H11/2→4I15/2, 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+ under a 980 nm semiconductor laser excitation at room temperature. The optimized doping concentrations for Yb3+ and Er3+ were 6.0 mol.% and 1.0 mol.%, respectively. Effects of ignition temperature and glycine-to-metal nitrate molar ratio on up-conversion emission intensity were also investigated. The log-log plots of luminescence intensity and pump power revealed that the 652–674 nm red emissions and 552 nm green emissions belonged to a two-photon process, while the 525 nm green emissions belonged to a three-photon process. The possible UC mechanisms were briefly discussed.展开更多
文摘The growth detects in Nd:YCa4O(BO3)3(Nd:YCOB) crystals were investigated by transmission synchrotron topography.It was found that growth striations were the primary defects in Nd:YCOB crystals.Grown-in dislocations.mosaic blocks and inclusions were also obsered in the crystals.The effect of temperature field on the formation of growth defects in the crystals was discussed.
基金Project supported by the National Natural Science Foundation of China(Grant No.61205130)the National Key Scientific Instruments Development Program of China(Grant No.2012YQ120047)the Fundamental Research Funds for the Central Universities of Ministry of Education of China(Grant No.K5051305008)
文摘A self-starting mode-locked femtosecond laser is accomplished with an oxoborate self-frequency doubling crystal Yb:YCa4O(BO3)3 (Yb:YCOB) as the gain medium and a semiconductor mirror as the saturable absorber. Pumped by a 976-nm fiber-coupled diode laser with 50-ktm core diameter, stable mode-locked laser pulses up to 430 mW were obtained at a repetition rate of 83.61 MHz under 5-W pump power. The autocorrelation measurement shows that the pulse duration is as short as 150 fs by assuming the sech2 pulse shape at a central wavelength of 1048 nm. This work has demonstrated a compact and reliable femtosecond laser source for prospective low-cost applications.
文摘Growth and morphology of neodymium or ytterbium doped calcium gadolinium yttrium oxoborate (Re∶Ca 4Gd x Y 1- x O(BO 3) 3(Re∶GdYCOB)Re =Nd,Yb; x =0-1)were systematically studied. Polycrystalline materials used for Re∶GdYCOB single crystals growth were synthesized by multistage solid phase reaction method.Re∶GdYCOB single crystals were grown by Czochralski technique.The pulling rates are 0.5-2mm/h and the rotation rates are 10-30r/min.Usually 65-75% polycrystalline materials can be transformed into good quality single crystals under our growth conditions. The structures of some as grown Re∶GdYCOB single crystals were measured by using a four circle diffractometer.The results measured show that the space group of the crystals is C 3 s Cm.The determined lattice constants of 8 at% Nd doped Ca 4YO(BO 3) 3 single crystal are a =0.8076nm, b =1.6020nm, c =0.3527nm , β =101.23°.
基金supported by the National Natural Science Foundation of China (Nos.61875199 and 61975208)Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB20000000)Science and Technology Service Network Initiative of the Chinese Academy of Sciences (No.KFJ-STS-QYZX-069)。
文摘End-pumped by a 976 nm diode laser,a high-repetition-rate Er:Yb:YAl3(BO3)4 microchip laser passively Q-switched by a Co2+:MgAl2 O4 crystal is reported.At a quasi-continuous-wave pump power of 20 W,a 1553 nm passively Q-switched laser with the repetition rate of 544 kHz,pulse duration of 8.3 ns,and pulse energy of 3.9 μJ was obtained.To the best of our knowledge,the 544 kHz is the highest reported value for the 1.5 μm passively Q-switched pulse laser.In the continuous-wave pumping experiment,the maximum repetition rate of 144 kHz with the pulse duration of 8.0 ns and pulse energy of 1.7 μJ was obtained at the incident pump power of 6.3 W.
基金supported by the National Natural Science Foundation of China (30670523)the Fundamental Research Funds for the Central Universities
文摘Novel up-conversion (UC) luminescent nano-powders, CaSc2O4:Yb3+:Er3+ were prepared with a combustion method at an ignition temperature as low as 200 oC. The CaSc2O4:Yb3+,Er3+ nano-powder had an orthorhombic CaFe2O4-type structure, and showed sphere-like morphology with an average diameter of about 30 nm. It gave strong green (525, 552 nm) and red (652–674 nm) up-conversion luminescence due to the 2H11/2→4I15/2, 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+ under a 980 nm semiconductor laser excitation at room temperature. The optimized doping concentrations for Yb3+ and Er3+ were 6.0 mol.% and 1.0 mol.%, respectively. Effects of ignition temperature and glycine-to-metal nitrate molar ratio on up-conversion emission intensity were also investigated. The log-log plots of luminescence intensity and pump power revealed that the 652–674 nm red emissions and 552 nm green emissions belonged to a two-photon process, while the 525 nm green emissions belonged to a three-photon process. The possible UC mechanisms were briefly discussed.