The nonlinear-optical coefficients of RCOB(R=Gd,Y)crystals are measured.The spatial distribution of deff effective nonlinear-optical coefficient is determined subsequently.Our experiments show that the maximum deff oc...The nonlinear-optical coefficients of RCOB(R=Gd,Y)crystals are measured.The spatial distribution of deff effective nonlinear-optical coefficient is determined subsequently.Our experiments show that the maximum deff occurs at the second quadrant.The second-harmonic-generation efficiency reaches 48%for a 6 mm-long,(113.2°,47.4°)-cut GdCOB,and 41.5%for a 5mm-long,(113°,36.5°)-cut YCOB,respectively.The intracavity frequency doubling of GdCOB is reported for the first time.展开更多
Large sized and optical quality GdCa_(4)O(BO_(3))_(3)(GdCOB)crystal with calcium partially substituted by strontium(Sr)ions was grown for the first time.The x-ray powder diffraction shows that the Sr ion has an effect...Large sized and optical quality GdCa_(4)O(BO_(3))_(3)(GdCOB)crystal with calcium partially substituted by strontium(Sr)ions was grown for the first time.The x-ray powder diffraction shows that the Sr ion has an effect on the cell parameters of the GdCOB crystal Second-harmonic generation(SHG)experiments were performed on the Sr:GdCOB and GdCOB crystals along the spatial phase-matching direction.The results show that the cw green laser output power is 1.04 W when the laser diode pump power is 10 W in the Nd:YVO_(4)/Sr:GdCOB intracavity laser.Considering the slope efficiency of Nd:YVO_(4) and the fundamental laser in cavity,the intracavity SHG conversion efficiency of the GdCOB crystal is 21%while it is 24%for the Sr:GdCOB crystal,the SHG conversion efficiency is improved by 14%.The effect of the Sr ions on the nonlinearity of the GdCOB crystal is also discussed by using the anion group theory.展开更多
Large size and high quality single crystals GdCa_(4)O(BO_(3))_(3) have been grown from platinum crucible under air atmosphere by the conventional rf-heating Czochralski method.The crystal growth conditions,growth habi...Large size and high quality single crystals GdCa_(4)O(BO_(3))_(3) have been grown from platinum crucible under air atmosphere by the conventional rf-heating Czochralski method.The crystal growth conditions,growth habits,and transmission spectra were investigated.The crystal is transparent in the visible and near-infrared region(320-2600nm).It has a good second harmonic generation phase-matching condition.The phase-matching experiment result is well consistent with the theoretical one.The frequency-doubling efficiency is 26.7% in the phase-matching angles θ=45o and ø=45.1o direction.展开更多
The rare-earth ions(Yb^(3+),Tm^(3+))and Li^(+),Bi^(3+)ions doped GdCa_(4)O(BO_(3))_(3) crystals were grown using the Czochralski pulling method.The second-harmonic-generation conversion efficiencies of the GdCOB:Yb an...The rare-earth ions(Yb^(3+),Tm^(3+))and Li^(+),Bi^(3+)ions doped GdCa_(4)O(BO_(3))_(3) crystals were grown using the Czochralski pulling method.The second-harmonic-generation conversion efficiencies of the GdCOB:Yb and GdCOB:Tm crystals are 31.3%and 33.3%,respectively,while the undoped GdCOB crystal is 27.9%.The conversion efficiencies of Yb^(3+),Tm^(3+)doped GdCOB are improved by 12%and 19%,respectively,compared to that of the undoped one.The conversion efficiencies of Li^(+),Bi^(3+)doped GdCOB crystals are 33%and 38.3%,which are improved by 15%and 37%as compared to that of the undoped crystal.The results are discussed using the anion group theory.展开更多
Second harmonic generation conversion efficiencies of Nd:YCOB and Nd:GdCOB were measured,the effective nonlinear coefficient(de_(ff))for both crystals at different phase-matching angles were estimated by comparison wi...Second harmonic generation conversion efficiencies of Nd:YCOB and Nd:GdCOB were measured,the effective nonlinear coefficient(de_(ff))for both crystals at different phase-matching angles were estimated by comparison with a KTP crystal.The self-frequency doubling laser performance c£these crystals were theoretically calculated by using these rfeff values and slope efficiency of the fundamental wave and lasing threshold.The results coincide very well.展开更多
The self-frequency doubling laser performance of Nd:GdCOB crystal cut in phase-matching direction(θ=66.3°,Ф=134.4°)was compared with the crystal cut in the direction of(θ=90°,Ф=46°).Results sho...The self-frequency doubling laser performance of Nd:GdCOB crystal cut in phase-matching direction(θ=66.3°,Ф=134.4°)was compared with the crystal cut in the direction of(θ=90°,Ф=46°).Results show that the former has a higher second-harmonic conversion efficiency than the latter.Using Ti:sapphire laser as pumping source,a maximum of 11.3mW of green light has been obtained with an incident power of 520mW.This corresponds to an optical-optical conversion efficiency of 2.2%.Laser threshold for self-frequency doubling operation is measured to be 1 mW.To our knowledge,this is the lowest threshold achieved so far.展开更多
The growth of lead tungstate(PWO)single crystals and their luminescence properties such as light yield,scintillation decay time,and transmittance were reported.The colourless PWO single crystal has been obtained by us...The growth of lead tungstate(PWO)single crystals and their luminescence properties such as light yield,scintillation decay time,and transmittance were reported.The colourless PWO single crystal has been obtained by using the presyntheses powder.Ba,Nb,and Mg ions were doped in the crystals and the Ba-doped crystal has a relatively short decay time.Annealed crystal was found having a better transmission spectrum than that of unannealed one.展开更多
A mutually pumped phase conjugator with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate is reported,in which both incoherent beams are incident upon the negative c face and th...A mutually pumped phase conjugator with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate is reported,in which both incoherent beams are incident upon the negative c face and they travel in geometric paths similar to the outline of two arches.The maximum reflectivity attains 21%.The tolerance of the output to both incident angles and positions is assessed.No apparent cross talk is observed.A cross-readout mechanism is also used to explain phase-conjugate reflectivity production.It is verified that the configuration can be realized easily for a crystal with two longer a sides.展开更多
A multistage four-wave mixing interaction region model resulting in self-pumped phase conjugation output of the incident beam is suggested to explain the experimental observations.The competition between forward and b...A multistage four-wave mixing interaction region model resulting in self-pumped phase conjugation output of the incident beam is suggested to explain the experimental observations.The competition between forward and backward two-wave mixing is demonstrated and used to explain the formation of the mechanism.The backscattering beams from random noise beams may be amplified by contradirectional two-wave mixing selectively and act as pumped beams from our experimental observations under a laser entering the negative c face of copper-doped potassium sodium strontium barium niobate crystal.The phase conjugation reflectivity of as high as 33%is measured.展开更多
A mutually pumped phase conjugator is demonstrated with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate,in which the beams travel in a geometric path similar to the outline of...A mutually pumped phase conjugator is demonstrated with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate,in which the beams travel in a geometric path similar to the outline of a sickle.The maximum reflectivity is up to 168%.Faster response times are measured and are also simulated as a function of incident beam power ratio.Four available input geometries are found.The phase conjugation signals exist wide range of angular and positional alignment.No apparent cross talk is observed.The faster build-up process of phase conjugation beams is tentatively explained.展开更多
The preparation procedure, the transmissivity, and the two-wave coupling properties of coppermodified potassium sodium strontium barium niobate (KNSBN) crystals are reported. The Cu ions doped in KNSBN can form two de...The preparation procedure, the transmissivity, and the two-wave coupling properties of coppermodified potassium sodium strontium barium niobate (KNSBN) crystals are reported. The Cu ions doped in KNSBN can form two deep energy levels. This means that they are able to act as centers for free charge carrier stimulation and recombination. The two-wave coupling gain coefficient of KNSBN: Cu is two times larger than that of KNSBN. The photorefractive sensitivity of KNSBN: Cu is estimated to be in the order of 10^(-3)cm^(2)/J.展开更多
基金Supported by the Key Program of the National Natural Science Foundation of China under Grant No.69890235the Key Program of Science and Technology Research of the Minis try of Education of China under Grant No.99182.
文摘The nonlinear-optical coefficients of RCOB(R=Gd,Y)crystals are measured.The spatial distribution of deff effective nonlinear-optical coefficient is determined subsequently.Our experiments show that the maximum deff occurs at the second quadrant.The second-harmonic-generation efficiency reaches 48%for a 6 mm-long,(113.2°,47.4°)-cut GdCOB,and 41.5%for a 5mm-long,(113°,36.5°)-cut YCOB,respectively.The intracavity frequency doubling of GdCOB is reported for the first time.
基金Supported by the National Natural Science Foundation of China under Grant No.69890235.
文摘Large sized and optical quality GdCa_(4)O(BO_(3))_(3)(GdCOB)crystal with calcium partially substituted by strontium(Sr)ions was grown for the first time.The x-ray powder diffraction shows that the Sr ion has an effect on the cell parameters of the GdCOB crystal Second-harmonic generation(SHG)experiments were performed on the Sr:GdCOB and GdCOB crystals along the spatial phase-matching direction.The results show that the cw green laser output power is 1.04 W when the laser diode pump power is 10 W in the Nd:YVO_(4)/Sr:GdCOB intracavity laser.Considering the slope efficiency of Nd:YVO_(4) and the fundamental laser in cavity,the intracavity SHG conversion efficiency of the GdCOB crystal is 21%while it is 24%for the Sr:GdCOB crystal,the SHG conversion efficiency is improved by 14%.The effect of the Sr ions on the nonlinearity of the GdCOB crystal is also discussed by using the anion group theory.
文摘Large size and high quality single crystals GdCa_(4)O(BO_(3))_(3) have been grown from platinum crucible under air atmosphere by the conventional rf-heating Czochralski method.The crystal growth conditions,growth habits,and transmission spectra were investigated.The crystal is transparent in the visible and near-infrared region(320-2600nm).It has a good second harmonic generation phase-matching condition.The phase-matching experiment result is well consistent with the theoretical one.The frequency-doubling efficiency is 26.7% in the phase-matching angles θ=45o and ø=45.1o direction.
基金Supported by the National Natural Science Foundation of China under Grant No.69890235the Research Fund for the Doctoral Program of Higher Education of China.
文摘The rare-earth ions(Yb^(3+),Tm^(3+))and Li^(+),Bi^(3+)ions doped GdCa_(4)O(BO_(3))_(3) crystals were grown using the Czochralski pulling method.The second-harmonic-generation conversion efficiencies of the GdCOB:Yb and GdCOB:Tm crystals are 31.3%and 33.3%,respectively,while the undoped GdCOB crystal is 27.9%.The conversion efficiencies of Yb^(3+),Tm^(3+)doped GdCOB are improved by 12%and 19%,respectively,compared to that of the undoped one.The conversion efficiencies of Li^(+),Bi^(3+)doped GdCOB crystals are 33%and 38.3%,which are improved by 15%and 37%as compared to that of the undoped crystal.The results are discussed using the anion group theory.
基金Supported by the National Natural Science Foundation of China under Grant No.68890235.
文摘Second harmonic generation conversion efficiencies of Nd:YCOB and Nd:GdCOB were measured,the effective nonlinear coefficient(de_(ff))for both crystals at different phase-matching angles were estimated by comparison with a KTP crystal.The self-frequency doubling laser performance c£these crystals were theoretically calculated by using these rfeff values and slope efficiency of the fundamental wave and lasing threshold.The results coincide very well.
文摘The self-frequency doubling laser performance of Nd:GdCOB crystal cut in phase-matching direction(θ=66.3°,Ф=134.4°)was compared with the crystal cut in the direction of(θ=90°,Ф=46°).Results show that the former has a higher second-harmonic conversion efficiency than the latter.Using Ti:sapphire laser as pumping source,a maximum of 11.3mW of green light has been obtained with an incident power of 520mW.This corresponds to an optical-optical conversion efficiency of 2.2%.Laser threshold for self-frequency doubling operation is measured to be 1 mW.To our knowledge,this is the lowest threshold achieved so far.
文摘The growth of lead tungstate(PWO)single crystals and their luminescence properties such as light yield,scintillation decay time,and transmittance were reported.The colourless PWO single crystal has been obtained by using the presyntheses powder.Ba,Nb,and Mg ions were doped in the crystals and the Ba-doped crystal has a relatively short decay time.Annealed crystal was found having a better transmission spectrum than that of unannealed one.
基金Supported by the Grant for a Key Research Project in Climbing Program from the State Science and Technology Commission of China.
文摘A mutually pumped phase conjugator with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate is reported,in which both incoherent beams are incident upon the negative c face and they travel in geometric paths similar to the outline of two arches.The maximum reflectivity attains 21%.The tolerance of the output to both incident angles and positions is assessed.No apparent cross talk is observed.A cross-readout mechanism is also used to explain phase-conjugate reflectivity production.It is verified that the configuration can be realized easily for a crystal with two longer a sides.
基金Supported by a Grant for a Key Research Project in Climbing Program from the State Science and Technology Commission of China.
文摘A multistage four-wave mixing interaction region model resulting in self-pumped phase conjugation output of the incident beam is suggested to explain the experimental observations.The competition between forward and backward two-wave mixing is demonstrated and used to explain the formation of the mechanism.The backscattering beams from random noise beams may be amplified by contradirectional two-wave mixing selectively and act as pumped beams from our experimental observations under a laser entering the negative c face of copper-doped potassium sodium strontium barium niobate crystal.The phase conjugation reflectivity of as high as 33%is measured.
基金Supported by a grant for a Key Research Project in Climbing Program from the State Science and Technology Commission of China。
文摘A mutually pumped phase conjugator is demonstrated with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate,in which the beams travel in a geometric path similar to the outline of a sickle.The maximum reflectivity is up to 168%.Faster response times are measured and are also simulated as a function of incident beam power ratio.Four available input geometries are found.The phase conjugation signals exist wide range of angular and positional alignment.No apparent cross talk is observed.The faster build-up process of phase conjugation beams is tentatively explained.
基金the National Natural Science Foundation of ChinaState Key Laboratory of Crystal Materials of Shandong University.
文摘The preparation procedure, the transmissivity, and the two-wave coupling properties of coppermodified potassium sodium strontium barium niobate (KNSBN) crystals are reported. The Cu ions doped in KNSBN can form two deep energy levels. This means that they are able to act as centers for free charge carrier stimulation and recombination. The two-wave coupling gain coefficient of KNSBN: Cu is two times larger than that of KNSBN. The photorefractive sensitivity of KNSBN: Cu is estimated to be in the order of 10^(-3)cm^(2)/J.
