端面泵浦掺Yb3+双包层光纤激光器

从双包层光纤激光器的速率方程出发，得到了光纤中泵浦光与激光的功率分布、输出功率与泵浦功率的关系、腔镜反射率及光纤长度对输出功率的影响。研究结果表明：输出激光功率与光纤长度及后腔镜反射率有很强的依赖关系，存在一个输出功率最大的最佳光纤长度。后腔镜反射率越大，输出激光功率越小；当光纤长度较短时，在输出端放置反射镜使泵浦光高反射，可以提高输出功率和效率。通过对端面泵浦掺Yb3+双包层光纤激光器进行理论分析和实验研究，得到输出激光的中心波长为1088.3nm，斜率效率为33.7%，最大输出功率为1.75W。     

100 W全光纤声光调Q光纤激光器实验研究

 报道了一台全光纤结构主振荡功率放大(MOPA)型掺镱脉冲光纤激光器,以光纤光栅为腔镜,光纤型声光调Q的光纤激光器为种子源,通过两级掺镱双包层光纤放大器实现功率放大。对声光调Q的光纤激光器输出特性进行了研究,比较了不同泵浦波长、不同重复频率对激光输出功率和脉冲宽度的影响,并实现了最短脉冲宽度25 ns、单脉冲能量45 μJ的脉冲激光输出。在重复频率50 kHz时,对脉冲宽度130 ns、平均功率0.6 W的种子光进行放大,得到了平均功率102.5 W、脉冲宽度约240 ns的激光输出。     

CW-COIL输出功率与输出孔径及光轴位置之间的依赖关系

 氧碘化学激光器由于复杂的动力学因素,激光介质的增益分布通常是不均匀的,这就使得激光输出功率并不完全随着激光输出孔径成线性增加,也由于这种增益分布的不均匀性,即使在激光输出孔径不变的情况下,激光输出功率也会随着光轴位置的改变而发生变化。为此,在激光器工作参数固定条件下,通过实验描述了激光输出功率与激光输出孔径及光轴位置之间存在着的一定的依赖关系。     

高功率半导体激光泵浦源研究进展

高功率半导体激光器是固体激光器和光纤激光器的主要泵浦源。激光泵浦源性能的大幅提升直接促进了固体激光器、光纤激光器等激光器的发展。主要介绍了8xx nm和9xx nm系列半导体激光泵浦源的最新研究进展,8xx nm单管输出功率已达18.8 W@95μm,巴条输出功率已达1.8 kW(QCW),9xx nm单管输出功率已达35 W@100μm,巴条输出功率已达1.98 kW(QCW)。谱宽<1 nm的窄谱宽半导体激光器输出功率可达14 W。展望了未来半导体激光器泵浦源的发展趋势。     

Nd:YAG陶瓷与单晶4F3/2–4I13/2跃迁的弱谱线多波长激光性能对比

报道了基于半导体激光端面抽运Nd:YAG的⁴F_3/2–⁴I_13/2 跃迁的弱谱线多波长激光输出. 实验对比了透明陶瓷与单晶材料的激光输出特性, 表明透明陶瓷和单晶材料荧光谱强度的略微差异, 导致了多波长输出时相同两个波长之间的激光强度比在两种材料中的差异. 基于两种耦合输出镜片, 激光阈值都在2 W左右. 在13.5 W的抽运功率下, 基于Nd:YAG透明陶瓷获得了输出功率4.05 W、强度比1 :2的1338与1356 nm双波长激光和输出功率3.65 W、强度比13 : 1的1356与1414 nm 双波长激光, 斜率效率分别达33.9% 和31.9%.     

激光诱导击穿光谱脉冲激光功率锁定的研究

激光诱导击穿光谱(laser-induced breakdown spectroscopy,LIBS)在煤质在线监测方面展现了突出的应用前景和研究价值。针对该技术在实际应用中会由于脉冲激光功率起伏导致的长期测量稳定性差的问题,建立了闭环负反馈式脉冲激光功率锁定装置,采用激光功率负反馈信号控制和锁定Nd∶YAG激光器输出功率。实验研究了不同分光比例脉冲激光器锁定在设定输出功率,同一分光比例激光器锁定在不同输出功率以及长时间运行时的功率锁定。结果表明,不同的分光比例对激光输出功率的锁定效果影响不大,分光比例越小,稳定速度越快;同一分光比例实现激光脉冲功率不同预设值的锁定以及在长时间运行时,采用此装置进行功率锁定后,激光输出功率处于预设区间内,RSD值由自由运行时的2.4%降低至1.1%。     

内腔级联拉曼光纤激光器输出特性的实验研究

采用标准单模石英光纤作为拉曼增益介质，光纤布拉格光栅作为谐振腔镜，研制了一台内腔级联拉曼光纤激光器。利用掺Yb双包层光纤激光器作为抽运源，实现了二级拉曼转换，在波长1176.8nm获得了309mW的最大输出功率，斜率效率接近51.5％。在小抽运功率下，发现拉曼光纤激光器的输出中存在重复周期约为2.9μs的脉冲序列；当抽运功率大于某一值时，上述脉冲消失，获得了十分稳定的连续输出。     

高功率全光纤激光器特性

介绍了采用国产光纤光栅研制的全光纤激光器,单端泵浦获得468 W的连续激光输出。从理论上分析了光纤光栅的反射率与波长的关系,计算了输出谱宽值,与实验测得的数据相符。全光纤激光器的光-光转换效率达到70%,且随着功率的增加,光纤光栅的中心波长有向长波方向漂移的趋势。在最高输出功率下180 s之内输出功率波动在0.04%以内。     

Yb3+:Y2O3透明陶瓷激光器获得5 W连续激光输出

用带尾纤输出的激光二极管作为抽运源,采用端面抽运10％Yb^3 ：Y2O3多晶透明陶瓷的方式获得了连续激光输出。抽运阈值功率为5．6W,当陶瓷介质吸收的抽运功率为31．11W时,Yb^3 ：Y2O3多晶透明陶瓷获得了最大连续激光输出功率5．48W。光—光转换效率为17．6％,斜率效率为25％。同时在激光实验过程中,没有发现饱和现象,因此采用更高功率的激光二极管作为抽运源,陶瓷的激光输出功率会得到进一步提高。这一研究成果表明,多晶透明陶瓷是一种非常有潜力的激光增益介质。     

Continuous wave operation of singly-doped Ho:LSO laser at room temperature

We present the room-temperature continuous-wave Ho:LSO laser single-pass-end-pumped by a diode-pumped Tm:YLF laser at 1.91 μm in this paper. Under different output couplers of 2.4, 5.0, and 14.0%, the laser output power and output spectrum of Ho:LSO laser operating at room temperature are investigated. The output wavelength of Ho:LSO laser was centered at 2106.5 nm with linewidth (FWHM) of about 3.2 nm. With T = 5.0%, the maximum output power of 2.4 W was achieved under the absorbed pump power of 11.1 W, corresponding to a slope efficiency of 38.0%.     

2277-W continuous-wave diode-pumped heat capacity laser

A high power continuous-wave (CW) diode-pumped Nd:YAG laser operated in heat capacity mode is demonstrated by use of two identical highly efficient diode-pumped laser heads placed in a plane-plane resonator. The laser heads are uniformly pumped with a five-fold symmetrical side-pumping configuration,and each head is able to output maximum output power of 2200 W at 808 nm. Under a total pump power of 4290 W, the output power of the laser at 1064 nm is up to 2277 W, corresponding to an optical-to-optical efficiency of 53.1%.     

Experimental study on kilowatt fiber laser in an all-fiber configuration

A high-power fiber laser in an all-fiber format is reported. The system consists of 36 pump ports, which use both counter and forward pump configuration. In the experiment, 1 008-W output power is obtained when 24 pump ports are used with a total pump power of 1477 W. The optical-to-optical conversion efficiency is 68% and the 3-dB bandwidth of laser output increases with output power. Presently, the output power is only limited by the pump source. It can be predicted that the laser power can be further scaled if more pump sources are utilized.     

Yb∶Y_2O_3陶瓷薄片激光器获得10.5 W连续激光输出

室温下采用中心波长约970 nm准直输出的大功率激光二极管模块作为抽运源,端面抽运双程吸收的腔型结构,抽运原子数分数为8%的Yb:Y2O3多晶透明陶瓷片获得连续激光输出。抽运阈值功率为7 W,当抽运功率达到35 W时,获得优化连续激光输出功率为10.5 W,光光转换效率为30%,斜率效率为37.5%。激光输出功率随抽运功率基本呈线性增长。采用更高功率抽运源、优化谐振腔结构和减小热效应的影响,Yb∶Y2O3陶瓷激光器的输出功率和效率将会得到进一步提高。     

Numerical simulation of a CW-pumped Cr:YAG passively Q-switched Yb:YAG pulsed laser

A general model of a CW-pumped passively Q-switched laser is presented which considers the pump power and excitation state of the absorber. The recovery time of the absorber is affected by the Q-switched laser pulse length and repetition rate, which results in changes of the output power, peak power and pulse duration of a CW-pumped passively Q-switched solid-state laser. At low pump power, the final inversion population density alters slowly by a small amount and the effect of the absorber's finite recovery time on laser output energy can be ignored. At high pump power, the final inversion population density increases quickly with pump power increase and the output energy decreases greatly. Simulation results of a CW-pumped, Cr:YAG Q-switched, Yb:YAG laser are reported. The numerical simulation results agree with the theoretical analytical analysis.     

Performance evaluation of VCSEL through single and multi mode fibers

This paper presents influence of the change in temperature of a vertical cavity surface emitting laser (VCSEL) on its output power. It is observed that with increase in temperature of laser its output power decrease. It is also observed that with decrease in threshold voltage of the laser output power increase. Decrease in output power due to increase in temperature can be compensated by increasing driving current. But increase in drive current decrease life of the laser. So a laser with lower threshold voltage can be used to operate at high temperature with long life. Propagation of VCSEL through single mode and multimode fiber is also studied. In single mode fiber only one propagation mode exists due to which signal can be transmitted to longer distances.     

双端泵浦保偏光纤激光器

 以两台808 nm半导体激光器LD1和LD2为泵浦源,对光纤激光器双端泵浦进行了研究,获得了6.5 W的激光输出。实验分别测出了LD1和LD2半导体激光器单端泵浦和双端泵浦时的输出功率,对双端泵浦输出功率与单端泵浦功率之和进行了比较,利用双端泵浦提高了泵浦效率和输出激光功率。同时测量了输出激光的偏振度,通过计算得到双端泵浦输出激光的偏振度为0.5。     

半导体激光无线传能中光伏电池转换效率

为选择合适的激光参量与光伏电池参量,以提高激光无线能量传输(LWPT)系统的能量转换效率,通过实验研究了LWPT系统中能量接收单元,也即光伏电池在半导体激光照射下的输出特性。通过波长为808 nm和915 nm的激光辐照GaAs和Si光伏电池,研究了不同激光功率密度、光伏电池温度、电池类型以及激光入射角度对光伏电池输出特性与能量转换效率的影响。实验中,在波长为808 nm的激光功率密度从0.06 W/cm2上升至0.37 W/cm2的过程中,Si电池的最大输出功率从0.12 W上升至0.32 W,能量转换效率从50.9%下降至21.2%;GaAs电池的最大输出功率从0.40 W上升到1.07 W,能量转换效率从57.9%下降至23.8%。随着激光功率密度的增加,光伏电池的输出功率先增加而后趋于饱和,但是高功率密度激光引起的电池温升会导致其光电转换效率的下降,所以激光功率密度的选择与光伏电池温度的控制是提高LWPT系统能量转换效率的关键因素。     

Optimization of linear cavity design of Yb-doped double-clad fiber laser

The output characteristics of a linear cavity Yb-doped double-clad fiber (DCF) laser, including the effects of fiber length, fiber loss, and output mirror reflectivity on laser output power and threshold pump power have been studied theoretically and experimentally. In this paper, the linear cavity of double-clad fiber laser (DCFL) was composed of a pair of fiber Bragg gratings, while the facet of fiber was anti-reflection (AR) coated at 1070nm to erase the Fresnel reflection. Analysis showed that the laser output increases as the reflectivity of the fiber Bragg grating used as the output mirror decreases. At last, under the pump power of 14.4 W, single-mode laser output at 1070 nm was up to 10.8 W, with slope efficiency of 75 %.     

A diode-pumped linear intracavity frequency doubled Nd:YAG rod laser with 40 ns pulse width and 73 W green output power

We analyzed a linear cavity for intracavity frequency doubling of a diode-pumped acousto-optic Q-switched Nd:YAG rod laser, and showed that a green laser beam with a short pulse width can be generated efficiently. A green laser output power of 73 W corresponding to the 83.9% of maximum IR output power was obtained with a 40 ns pulse width at a 10 kHz repetition rate. A green output power of 40 W with a 35 ns pulse width was measured at a 5 kHz repetition rate. Minimum laser pulse width of approximately 32 ns was obtained around 1 kHz repetition rate for both green and IR laser beams.     

Laser diode and pumped Cr:Yag passively Q-switched yellow-green laser at 543 nm

Efficient and compact yellow green pulsed laser output at 543 nm is generated by frequency doubling of a passively Q-switched end diode-pumped Nd:YVO₄ laser at 1086 nm under the condition of sup-pressing the higher gain transition near 1064 nm. With 15 W of diode pump power and the frequency doubling crystal LBO, as high as 1.58 W output power at 543 nm is achieved. The optical to optical conversion efficiency from the corresponding Q-switched fundamental output to the yellow green output is 49%. The peak power of the Q-switched yellow green pulse laser is up to 30 kW with 5 ns pulse duration. The output power stability over 8 hours is better than 2.56% at the maximum output power. To the best of our knowledge, this is the highest watt-level laser at 543 nm generated by frequency doubling of a passively Q-switched end diode pumped Nd:YVO₄ laser at 1086 nm.