音频段压缩态光场是进行连续变量量子精密测量重要的量子资源.本文利用自制的低噪声连续单频671 nm/1.34μm双波长激光器作为抽运源,抽运基于周期极化磷酸氧钛钾晶体的简并光学参量振荡器,进行了光通信波段1.34μm连续变量音频段真空压...音频段压缩态光场是进行连续变量量子精密测量重要的量子资源.本文利用自制的低噪声连续单频671 nm/1.34μm双波长激光器作为抽运源,抽运基于周期极化磷酸氧钛钾晶体的简并光学参量振荡器,进行了光通信波段1.34μm连续变量音频段真空压缩态光场的实验制备.当简并光学参量振荡器运转于阈值以下参量反放大状态时,抽运光场功率为95 mW,本地振荡光功率为60μW时,在分析频率8—100 k Hz范围内研制出1.34μm真空压缩态光场.在分析频率36 k Hz处,压缩态光场的最大压缩度达5.0 d B;在音频频率8k Hz处,压缩态光场的压缩度达3.0 d B.音频段1.34μm压缩态光场可用于实现基于光纤的量子精密测量.展开更多
Recent innovations in thulium laser techniques have allowed application in the treatment of bladder cancer.Laser en bloc resection of bladder cancer is a transurethral procedure that may offer an alternative to the co...Recent innovations in thulium laser techniques have allowed application in the treatment of bladder cancer.Laser en bloc resection of bladder cancer is a transurethral procedure that may offer an alternative to the conventional transurethral resection procedure.We conducted a review of basic thulium laser physics and laser en bloc resection procedures and summarized the current clinical literature with a focus on complications and outcomes.Literature evidence suggests that thulium laser techniques including smooth incision,tissue vaporization,and en bloc resection represent feasible,safe,and effective procedures in the treatment of bladder cancer.Moreover,these techniques allow improved specimen orientation and accurate determination of invasion depth,facilitating correct diagnosis,restaging,and reevaluation of the need for a second resection.Nonetheless,large-scale multicentre studies with longer follow-up are warranted for a robust assessment.The present review is meant as a quick reference for urologists.展开更多
The purpose of the current ex vivo study was to compare the speed of vaporesection of human prostatic tissue with benign prostatic hyperplasia （BPH） and the depth of tissue damage using 70- and 120-W 2-tim laser dev...The purpose of the current ex vivo study was to compare the speed of vaporesection of human prostatic tissue with benign prostatic hyperplasia （BPH） and the depth of tissue damage using 70- and 120-W 2-tim laser devices. Fresh prostatic tissue specimens were obtained from five patients by open prostatectomy, and were divided into separate groups （70 and 120 W） based on the energy of the laser output （70 and 120 W, respectively）. The vaporesection speed, coagulation zone depth and the necrotic tissue layer in the prostatic tissue were evaluated. The current result showed that the speeds （mean±s.d.） of vaporesection were 5.21±0.66 and 10.39±1.15 g/5 min for the 70 and 120 W groups, respectively （P=0.000）. There was no difference in the depth of necrosis/ coagulation （0.98±0.1310.30±0.09 and 0.99±0.12/0.31±0.08 mm） for the 70 and 120 W groups, respectively. In conclusion, both 70- and 120-W 2μm laser devices had superficial tissue damage during the vaporesection of human prostate tissue; moreover, the 120-W laser offers a higher vaporesection speed than the 70-W laser.展开更多
An efficient and high-power diode-laser single-end-pumped Nd：YVO4 laser with cw emission at 1342nm is presented. With a crystal single-end-pumped by a fibre-coupled diode laser, an output power of 7.36 W is obtained ...An efficient and high-power diode-laser single-end-pumped Nd：YVO4 laser with cw emission at 1342nm is presented. With a crystal single-end-pumped by a fibre-coupled diode laser, an output power of 7.36 W is obtained from the laser cavity of concave-convex, eorresponding to an optical-to-optical conversion efficiency of 32.8%. The laser is operated in TEM00 mode with small rms noise amplitude of 0.3%. This represents, to the best of our knowledge, the highest power obtained from a diode-laser single-end-pumped Nd：YVO4 cw laser at 1342nm 80 far.展开更多
The excellent optical properties of MXene provide new opportunities for short-pulse lasers. A diode-pumped passively Q-switched laser at 1.3 μm wavelength with MXene Ti3C2Tx as saturable absorber was achieved for the...The excellent optical properties of MXene provide new opportunities for short-pulse lasers. A diode-pumped passively Q-switched laser at 1.3 μm wavelength with MXene Ti3C2Tx as saturable absorber was achieved for the first time. The stable passively Q-switched laser has 454 ns pulse width and 162 kHz repetition rate at 4.5 W incident pumped power. The experimental results show that the MXene Ti3C2Tx saturable absorber can be used as an optical modulator to generate short pulse lasers in a solid-state laser field.展开更多
We integrally demonstrate 2μm mode-locked pulses performances in all-fiber net anomalous dispersion cavity.Stable mode-locking operations with the center wavelength around 1950–1980 nm can be achieved by using the n...We integrally demonstrate 2μm mode-locked pulses performances in all-fiber net anomalous dispersion cavity.Stable mode-locking operations with the center wavelength around 1950–1980 nm can be achieved by using the nonlinear polarization rotation structure and properly designing the dispersion management component.Conventional soliton is firstly obtained with a total anomalous dispersion cavity.Due to the contribution of commercial ultra-high numerical aperture fibers,net dispersion is reduced to-0.077 ps2.So that stretched pulse with 19.4 nm optical bandwidth is obtained and the de-chirped pulse-width can reach 312 fs using extra-cavity compression.Under pump power greater than 890 mW,stretched pulse can evolve into noise-like pulse with 41.3 nm bandwidth.The envelope and peak of such broadband pulse can be compressed with up to 2.2 ps and 145 fs,respectively.The single pulse energy of largely chirped stretched and noise-like pulse can reach 1.785 nJ and 1.53 nJ,respectively.Furthermore,extra-cavity compression can also contribute to a significant increase of peak power.展开更多
We report a low noise continuous-wave （CW） single-frequency 1.5-μm laser source obtained by a singly resonant optical parametric oscillator （SRO） based on periodically poled lithium niobate （PPLN）. The SRO was ...We report a low noise continuous-wave （CW） single-frequency 1.5-μm laser source obtained by a singly resonant optical parametric oscillator （SRO） based on periodically poled lithium niobate （PPLN）. The SRO was pumped by a CW single-frequency Nd：YVO4 laser at 1.06μm. The 1.02 W of CW single-frequency signal laser at 1.5 μm was obtained at pump power of 6 W. At the output power of around 0.75 W, the power stability was better than ±l.5% and no mode-hopping was observed in 30 min and frequency stability was better than 8.5 MHz in 1 min. The signal wavelength could be tuned from 1.57 to 1.59 μm by varying the PPLN temperature. The 1.5-μm laser exhibits low noise characteristics, the intensity noise of the laser reaches the shot noise limit （SNL） at an analysis frequency of 4 MHz and the phase noise is less than 1 dB above the SNL at analysis frequencies above 10 MHz.展开更多
We report high-power single-spatial-mode type-I GaSb-based tapered lasers fabricated on the InGaSb/AlGaAsSb material system. A straight ridge and three different tapered waveguide structures with varying flare angles ...We report high-power single-spatial-mode type-I GaSb-based tapered lasers fabricated on the InGaSb/AlGaAsSb material system. A straight ridge and three different tapered waveguide structures with varying flare angles are fabricated to optimize the output power and spatial-mode performance. The best devices exhibit single-spatial-mode operation with room-temperature output power up to 350？mW in continuous-wave mode at an emission wavelength around 2.0？μm with a very small far-field lateral divergence angle, which is beyond state of the art in terms of single-spatial-mode output power.展开更多
Microstructure of the deepest zone of high speed steel W6Mo5Cr4V2(M2)melt after laser fu-sion was found to be so fine as the ehill zone of a solidified ingot.When narrower chill zoneformed,the long columnar dendrites ...Microstructure of the deepest zone of high speed steel W6Mo5Cr4V2(M2)melt after laser fu-sion was found to be so fine as the ehill zone of a solidified ingot.When narrower chill zoneformed,the long columnar dendrites grow into the melt and then the fine equiaxed cellularstructure appears in upper melt region nearly surface.The substructure of cellular grains anddendrites was observed to consist of martensite and retained austenile,while the carbides asM_6C_■ Cr_7C_3 and MC distributed at their boundaries.It is believed that the highermicrohardness up to HV_(0.1)=865-960 of the laser fused structure of the alloy is due to the oc-currence of martensite.展开更多
Optimization of the high power single-lateral-mode double-trench ridge waveguide semiconductor laser based on InGaAsP/InP quantum-well heterostructures with a separate confinement layer is reported. Two different wave...Optimization of the high power single-lateral-mode double-trench ridge waveguide semiconductor laser based on InGaAsP/InP quantum-well heterostructures with a separate confinement layer is reported. Two different waveguide structures of Fabry-Perot lasers emitting at a wavelength of 1.55 μm are fabricated. The influence of an effective lateral refractive index step on the maximum output power is investigated. A cw single mode output power of 165mW is obtained for a 1-mm-long uncoated laser.展开更多
We propose and demonstrate a synchronously pumped mode-locked Tm-doped fiber（TDF） laser without any extra mode-locking elements. Pumped by a 1.56 μm pulse fiber laser, the TDF laser generates 1.17 ps pulses with a ...We propose and demonstrate a synchronously pumped mode-locked Tm-doped fiber（TDF） laser without any extra mode-locking elements. Pumped by a 1.56 μm pulse fiber laser, the TDF laser generates 1.17 ps pulses with a spectral width of 9.7 nm and a repetition rate of 9.33 MHz. The emission wavelength is tunable along with the cavity length detuning in a wide range of 3 mm. The high detuning toleration is beneficial to achieve high temperature and vibration stability in all-fiber configuration lasers.展开更多
800 MPa grade new ultra-low carbon bainitic （NULCB） steel is the recently developed new generation steel. The microstructure in the coarse-grained heat affected zone （CGHAZ） of NULCB steel under laser welding cond...800 MPa grade new ultra-low carbon bainitic （NULCB） steel is the recently developed new generation steel. The microstructure in the coarse-grained heat affected zone （CGHAZ） of NULCB steel under laser welding conditions was investigated by thermal simulation. The influence of the cooling time from 800℃ to 500℃.t8/5 （0.3-30 s）, on the microstructure of the CGHAZ was discussed. The experimental results indicate that the microstructnre of the CGHAZ is only the granular bainite which consists of bainitic ferrite （BF） lath and M-A constituent while t8/5 is 0.3-30 s. The M-A constituent consists of twinned martensite and residual austenite, and the change of the volume fraction of the residual austenite in the M-A constituent is very small when t8/5 is between 0.3 and 30 s. The morphology of the M-A constituent obviously changes with the variation of t8/5.As t8/5 increases, tile average width, gross and shape parameter of the M-A constituent increase, while the line density of the M-A constituent decreases.展开更多
文摘音频段压缩态光场是进行连续变量量子精密测量重要的量子资源.本文利用自制的低噪声连续单频671 nm/1.34μm双波长激光器作为抽运源,抽运基于周期极化磷酸氧钛钾晶体的简并光学参量振荡器,进行了光通信波段1.34μm连续变量音频段真空压缩态光场的实验制备.当简并光学参量振荡器运转于阈值以下参量反放大状态时,抽运光场功率为95 mW,本地振荡光功率为60μW时,在分析频率8—100 k Hz范围内研制出1.34μm真空压缩态光场.在分析频率36 k Hz处,压缩态光场的最大压缩度达5.0 d B;在音频频率8k Hz处,压缩态光场的压缩度达3.0 d B.音频段1.34μm压缩态光场可用于实现基于光纤的量子精密测量.
文摘Recent innovations in thulium laser techniques have allowed application in the treatment of bladder cancer.Laser en bloc resection of bladder cancer is a transurethral procedure that may offer an alternative to the conventional transurethral resection procedure.We conducted a review of basic thulium laser physics and laser en bloc resection procedures and summarized the current clinical literature with a focus on complications and outcomes.Literature evidence suggests that thulium laser techniques including smooth incision,tissue vaporization,and en bloc resection represent feasible,safe,and effective procedures in the treatment of bladder cancer.Moreover,these techniques allow improved specimen orientation and accurate determination of invasion depth,facilitating correct diagnosis,restaging,and reevaluation of the need for a second resection.Nonetheless,large-scale multicentre studies with longer follow-up are warranted for a robust assessment.The present review is meant as a quick reference for urologists.
文摘The purpose of the current ex vivo study was to compare the speed of vaporesection of human prostatic tissue with benign prostatic hyperplasia （BPH） and the depth of tissue damage using 70- and 120-W 2-tim laser devices. Fresh prostatic tissue specimens were obtained from five patients by open prostatectomy, and were divided into separate groups （70 and 120 W） based on the energy of the laser output （70 and 120 W, respectively）. The vaporesection speed, coagulation zone depth and the necrotic tissue layer in the prostatic tissue were evaluated. The current result showed that the speeds （mean±s.d.） of vaporesection were 5.21±0.66 and 10.39±1.15 g/5 min for the 70 and 120 W groups, respectively （P=0.000）. There was no difference in the depth of necrosis/ coagulation （0.98±0.1310.30±0.09 and 0.99±0.12/0.31±0.08 mm） for the 70 and 120 W groups, respectively. In conclusion, both 70- and 120-W 2μm laser devices had superficial tissue damage during the vaporesection of human prostate tissue; moreover, the 120-W laser offers a higher vaporesection speed than the 70-W laser.
文摘An efficient and high-power diode-laser single-end-pumped Nd：YVO4 laser with cw emission at 1342nm is presented. With a crystal single-end-pumped by a fibre-coupled diode laser, an output power of 7.36 W is obtained from the laser cavity of concave-convex, eorresponding to an optical-to-optical conversion efficiency of 32.8%. The laser is operated in TEM00 mode with small rms noise amplitude of 0.3%. This represents, to the best of our knowledge, the highest power obtained from a diode-laser single-end-pumped Nd：YVO4 cw laser at 1342nm 80 far.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61475089 and 61435010)the Science and Technology Planning Project of Guangdong Province,China(Grant No.2016B050501005)the Science and Technology Innovation Commission of Shenzhen,China(Grant No.KQTD2015032416270385)
文摘The excellent optical properties of MXene provide new opportunities for short-pulse lasers. A diode-pumped passively Q-switched laser at 1.3 μm wavelength with MXene Ti3C2Tx as saturable absorber was achieved for the first time. The stable passively Q-switched laser has 454 ns pulse width and 162 kHz repetition rate at 4.5 W incident pumped power. The experimental results show that the MXene Ti3C2Tx saturable absorber can be used as an optical modulator to generate short pulse lasers in a solid-state laser field.
基金This work was supported in part by the National Natural Science Foundation of China 61975021in part by the Science and Technology Project of Jilin Province under Grant 20170414041GHin part by the Research Project of Jilin Provincial Education Department under Grant JJKH20181090KJ.
文摘We integrally demonstrate 2μm mode-locked pulses performances in all-fiber net anomalous dispersion cavity.Stable mode-locking operations with the center wavelength around 1950–1980 nm can be achieved by using the nonlinear polarization rotation structure and properly designing the dispersion management component.Conventional soliton is firstly obtained with a total anomalous dispersion cavity.Due to the contribution of commercial ultra-high numerical aperture fibers,net dispersion is reduced to-0.077 ps2.So that stretched pulse with 19.4 nm optical bandwidth is obtained and the de-chirped pulse-width can reach 312 fs using extra-cavity compression.Under pump power greater than 890 mW,stretched pulse can evolve into noise-like pulse with 41.3 nm bandwidth.The envelope and peak of such broadband pulse can be compressed with up to 2.2 ps and 145 fs,respectively.The single pulse energy of largely chirped stretched and noise-like pulse can reach 1.785 nJ and 1.53 nJ,respectively.Furthermore,extra-cavity compression can also contribute to a significant increase of peak power.
基金supported by the National Natural Science Foundation of China(Grant No.60878003)the Science Fund for Excellent Research Team of the National Natural Science Foundation of China(Grant No.60821004)the National Basic Research Program of China(Grant No.2010CB923101)
文摘We report a low noise continuous-wave （CW） single-frequency 1.5-μm laser source obtained by a singly resonant optical parametric oscillator （SRO） based on periodically poled lithium niobate （PPLN）. The SRO was pumped by a CW single-frequency Nd：YVO4 laser at 1.06μm. The 1.02 W of CW single-frequency signal laser at 1.5 μm was obtained at pump power of 6 W. At the output power of around 0.75 W, the power stability was better than ±l.5% and no mode-hopping was observed in 30 min and frequency stability was better than 8.5 MHz in 1 min. The signal wavelength could be tuned from 1.57 to 1.59 μm by varying the PPLN temperature. The 1.5-μm laser exhibits low noise characteristics, the intensity noise of the laser reaches the shot noise limit （SNL） at an analysis frequency of 4 MHz and the phase noise is less than 1 dB above the SNL at analysis frequencies above 10 MHz.
基金Supported by the National Basic Research Program of China under Grant Nos 2014CB643903 and 2013CB932904the National Natural Science Foundation of China under Grant Nos 61435012 and 61290303the Strategic Priority Research Program(B) of the Chinese Academy of Sciences under Grant No XDB01010200
文摘We report high-power single-spatial-mode type-I GaSb-based tapered lasers fabricated on the InGaSb/AlGaAsSb material system. A straight ridge and three different tapered waveguide structures with varying flare angles are fabricated to optimize the output power and spatial-mode performance. The best devices exhibit single-spatial-mode operation with room-temperature output power up to 350？mW in continuous-wave mode at an emission wavelength around 2.0？μm with a very small far-field lateral divergence angle, which is beyond state of the art in terms of single-spatial-mode output power.
文摘Microstructure of the deepest zone of high speed steel W6Mo5Cr4V2(M2)melt after laser fu-sion was found to be so fine as the ehill zone of a solidified ingot.When narrower chill zoneformed,the long columnar dendrites grow into the melt and then the fine equiaxed cellularstructure appears in upper melt region nearly surface.The substructure of cellular grains anddendrites was observed to consist of martensite and retained austenile,while the carbides asM_6C_■ Cr_7C_3 and MC distributed at their boundaries.It is believed that the highermicrohardness up to HV_(0.1)=865-960 of the laser fused structure of the alloy is due to the oc-currence of martensite.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61274046 and 61474111the National Basic Research Program of China under Grant No 2013AA014202
文摘Optimization of the high power single-lateral-mode double-trench ridge waveguide semiconductor laser based on InGaAsP/InP quantum-well heterostructures with a separate confinement layer is reported. Two different waveguide structures of Fabry-Perot lasers emitting at a wavelength of 1.55 μm are fabricated. The influence of an effective lateral refractive index step on the maximum output power is investigated. A cw single mode output power of 165mW is obtained for a 1-mm-long uncoated laser.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61675188 and 61875052the Open Fund of Key Laboratory Pulse Power Laser Technology of China under Grant No SKL2016KF03
文摘We propose and demonstrate a synchronously pumped mode-locked Tm-doped fiber（TDF） laser without any extra mode-locking elements. Pumped by a 1.56 μm pulse fiber laser, the TDF laser generates 1.17 ps pulses with a spectral width of 9.7 nm and a repetition rate of 9.33 MHz. The emission wavelength is tunable along with the cavity length detuning in a wide range of 3 mm. The high detuning toleration is beneficial to achieve high temperature and vibration stability in all-fiber configuration lasers.
文摘800 MPa grade new ultra-low carbon bainitic （NULCB） steel is the recently developed new generation steel. The microstructure in the coarse-grained heat affected zone （CGHAZ） of NULCB steel under laser welding conditions was investigated by thermal simulation. The influence of the cooling time from 800℃ to 500℃.t8/5 （0.3-30 s）, on the microstructure of the CGHAZ was discussed. The experimental results indicate that the microstructnre of the CGHAZ is only the granular bainite which consists of bainitic ferrite （BF） lath and M-A constituent while t8/5 is 0.3-30 s. The M-A constituent consists of twinned martensite and residual austenite, and the change of the volume fraction of the residual austenite in the M-A constituent is very small when t8/5 is between 0.3 and 30 s. The morphology of the M-A constituent obviously changes with the variation of t8/5.As t8/5 increases, tile average width, gross and shape parameter of the M-A constituent increase, while the line density of the M-A constituent decreases.
