Greatly improved stability of passively Q-switched Ce:Nd:YAG laser by using corner cube prism

In order to solve the hard problem of laser instability, a miniature Cr⁴⁺:YAG Q-switched Ce:Nd:YAG laser with a retroreflecting corner cube prism is demonstrated. The corner cube prism is insensitive to misalignment in any direction. Laser cavity with the prism is found to meet the condition of violent change of environment temperature and the variation of thermal lens of laser crystal by our experiment. Compared with flat-flat cavity, stability of the laser with a retroreflecting corner cube prism is improved remarkably.     

A thermally-insensitive passively Q-switched Cr:YAG/Nd:YAG laser

A passively Q-switched laser with Cr⁴⁺:YAG/Nd:YAG composite crystal using a corner cube prism cavity has been realized, in which the corner cube prism is the key element as it aids the compensation of the thermal lens effect of laser crystal. Compared with plane–plane mirror cavities under the same conditions, the stability of the laser performance using the corner cube prism cavity was improved remarkably over temperatures ranging from −40 to 65 °C. The decrease of Nd:YAG stimulated emission cross section with temperature was considered to be the main reason for the increase of average output pulse energy under the same cycle for the two different cavities when the ambient temperature changed −40 to 65 °C. The mode properties produced by the prism cavity were analyzed, and the theoretical results were verified by experimental observations.     

Excellent stability of laser passively Q-switched with a retroreflecting corner cube prism

A miniature Cr⁴⁺:YAG Q-switched, repetitive operation, conductive cooling Nd:YAG laser with a retroreflecting corner cube prism is demonstrated. The corner cube prism which is insensitive to misalignment in any direction makes it useful for the laser to adapt to the violent change of ambient temperature and also makes the laser cavity insensitive to the variation of thermal lens of the crystal. The laser has excellent stability of the average output pulse energy and the threshold voltage under different ambient temperature of −40, 25, and 55°C.     

角锥型全固态非平面环形激光器473 nm单频运转

提出并实现了由热键合直角棱镜与角锥棱镜构成的新型946 nm及473 nm单频非平面环形激光器.直角棱镜由无掺杂的YAG晶体和2 mm厚的Nd∶YAG晶体热键合形成,可提供激光增益、光路闭合及对946 nm激光起偏等多种复合功能.角锥棱镜由熔融石英材料构成,在环形永磁铁作用下,提供法拉第旋转作用.实验上实现了该结构的946 nm腔内倍频,并获得了473 nm单频单向激光输出.     

角锥型全固态非平面环形激光器473 nm单频运转

提出并实现了由热键合直角棱镜与角锥棱镜构成的新型946 nm及473 nm单频非平面环形激光器.直角棱镜由无掺杂的YAG晶体和2 mm厚的Nd∶YAG晶体热键合形成,可提供激光增益、光路闭合及对946 nm激光起偏等多种复合功能.角锥棱镜由熔融石英材料构成,在环形永磁铁作用下,提供法拉第旋转作用.实验上实现了该结构的946 nm腔内倍频,并获得了473 nm单频单向激光输出.     

Pulsed Nd:YAG passive Q-switched laser using Cr4+:YAG crystal

In this paper, we report the experimental results of a pulsed flash lamp Nd:YAG laser at wavelength of 1064 nm and Q-switched by Cr⁴⁺:YAG solid state saturable absorber. We have obtained the output energy (E) and pulse- width (τ_p) of this laser for various initial transmissions of this saturable absorber. Furthermore, the effect of reflectivity of the output coupler (R), diameter of the rod (d), and optical length of the cavity (l) on this laser output data have been investigated. We have used the corner cube as a back mirror, which shows high laser stability and better brightness. We have obtained pulse-width 15 ns with 31 mJ output energy. We have also analyzed this laser theoretically and analytically, which agrees well with our corresponding experimental results.     

Development of a Single-Longitudinal-Mode Ho:YAG Laser Based on Corner Cube

We present a Tm-doped fiber laser pumped Fabry-Perot etalons Ho:YAG laser based on a corner cube.A maximum single-longitudinal-mode and fundamental transverse mode output power of 478 mW at the waveiength of 2091.06 nm is achieved with a pump power of 16.3 W,corresponding to an opticai-to-optical efficiency of 2.9%and a slope efficiency of 7.9%.The single-longitudinal-mode and fundamental transverse mode are less sensitive to the rotating of the corner cube.The results indicate the potential impact of a single-longitudinal-mode Ho:YAG laser with corner cube geometry to improve the anti-maladjustment stability.     

折叠式角锥棱镜谐振腔的偏振特性理论与实验研究

建立了角锥棱镜的偏振模型,分析了角锥棱镜对入射线偏振光的偏振态的影响,分析表明角锥棱镜的单个入射区域存在特殊的偏振方向,该方向的线偏振光被角锥棱镜反射后仍然是线偏振光。利用角锥棱镜的该特性设计了腔内存在线偏振光振荡的角锥棱镜激光谐振腔,能够使用电光开关调Q,在振动环境中具有较好的抗失调稳定性。研制了激光器样机并进行了实验,在重复频率为10 Hz时,输出激光单脉冲能量大于300 mJ,光束质量因子β值在2左右,实验结果也表明角锥棱镜的棱和顶点并不影响输出激光的光束质量。     

角锥棱镜腔Nd:YAG/Cr4+:YAG被动锁模激光器的研究

理论分析并数值模拟了腔内光强随角锥棱镜旋转的变化,实验证明在角锥棱镜腔Nd:YAG/Cr4 :YAG被动锁模激光器中,偏振耦合输出得到了锁模深度和锁模几率近乎100%的线偏振被动锁模脉冲输出.通过旋转角锥棱镜改变偏振耦合输出、调节腔内光强,可以得到被动锁模和被动调Q两种状态的脉冲输出,脉冲能量166.5 mJ/pulse,脉冲动静比高达59.7%.     

球面角锥棱镜非稳腔钕玻璃激光器

为了将虚共焦非稳腔输出光束质量高和角锥棱镜谐振腔具有免调试的优点结合到一起,提出了用球面角锥棱镜构成虚共焦非稳腔的方案。利用已有虚共焦非稳腔钕玻璃激光器,设计加工了一球面角锥棱镜非稳腔钕玻璃激光器。模拟计算了两谐振腔输出光束的模式分布,然后对两钕玻璃激光器进行了实验对比研究。结果表明:实验得到的模式分布与模拟计算结果相吻合,球面角锥棱镜非稳腔钕玻璃激光器与虚共焦非稳腔钕玻璃激光器分别获得了最大2176.9J和2340.6J的能量输出,二者的电光效率与束散基本相同,分别为4.3%,0.30mrad和4.6%,0.26mrad。     

Passively Q-switched Nd3+:YAG laser with corner cube

A passively Q-switched Nd3+:YAG laser with corner cube is theoretically and experimentally studied. We analyze the polarization variation in cavity and simulate the peak power, pulse energy and pulse width changed with the rotation angle of corner cube numerically. An experiment is made to verify the theoretical results. With rotating the angle of corner cube about the axis the variation range of peak power is 1.77 MW (from 10.36 to 8.59 MW), and that of pulse energy is 14.9 mJ (from 159.5 to 174.4 mJ), the fluctuation of pulse width is 2.95 ns. The experimental results agree with the theoretical analysis to the extent of variation rules. The most dynamic to static energy ratio of 62.5% is achieved.     

An Intracavity-Triggered Passively-Switched Nd:YVO<Subscript>4</Subscript> Laser

We demonstrate an intracavity-triggered passively Q-switched Nd:YVO₄ laser within a diode-end-pumped configuration. We employ a Cr⁴⁺:YAG saturable absorber as the passive Q switch and an Nd:LiYF₄ (YLF) laser as the laser triggering of the Q-switched laser. Since we use the same Cr⁴⁺:YAG crystal and output coupler with the Nd:YVO₄ laser, the Cr⁴⁺:YAG Q switch is triggered inside the Nd:YLF laser cavity. As a result, the timing jitter in standard deviation of Nd:YVO₄ laser can be reduced to 16 ns.     

角隅全反镜谐振腔激光器的输出特性

 在高功率脉冲气体激光器中,用角隅反射镜作为全反镜,平行平面镜作为输出镜构成角隅全反镜谐振腔。对角隅腔激光器的输出特性和抗失调稳定性进行了研究,并与平凹腔和平平腔激光器进行了比较。实验结果表明：在角隅全反镜失调角为16 mrad时,角隅腔激光器的单脉冲输出能量下降9.2%,且近场输出光斑没有明显变化;而凹面全反镜失调角仅为0.4 mrad时,平凹腔激光器输出能量下降了9%,近场输出光斑严重变形。在输出镜正前方3.12 m处测量,当角隅镜偏转16.3 mrad时,激光器输出光斑与标准状态时的输出光斑重合;凹面全反镜失调角为0.4 mrad时,激光器输出光斑位移14 mm。经模式仪分析表明,角隅腔激光器近场光强分布均匀。     

LD端面泵浦Cr4:YAG被动调Q激光器输出特性研究

对激光二极管端面泵浦Cr⁴⁺:YAG被动调QNd:YAG激光器输出特性进行了实验研究.实验研究发现,激光器输出功率及脉冲重复频率随谐振腔长度增大而增大.为解释这一实验现象,测量了泵浦光斑在激光晶体内尺寸,同时计算了激光晶体及Cr⁴⁺:YAG晶体内的基模激光光斑半径随谐振腔长度变化.分析结果表明:激光晶体内泵浦光斑尺寸远小于激光晶体内基模光斑半径,腔模间交叠效率较低;当腔长增加时,激光晶体内的基模激光光斑减小,腔模间交叠效率增加,从而导致输出功率及脉冲重复频率随腔长增加而增加;另外,Cr⁴⁺:YAG晶体内光斑半径也随谐振腔长度减小,引起Cr⁴⁺:YAG晶体漂白时间缩短,导致脉冲重复频率随腔长增加而增加.     

角锥棱镜谐振腔激光模式模拟研究

为了探究角锥棱镜谐振腔激光模式,以角锥-平面镜腔为例,将角锥棱镜等效为衍射光栅,考虑角锥镜棱宽在谐振腔中的衍射效应以及二面角误差引起的附加相位分布对谐振腔激光模式的影响,在光学谐振腔理论的基础上,建立了求解本征模式的理论分析模型.采用快速傅里叶法数值模拟不同腔长、角锥镜棱宽和二面角误差情况下该无源谐振腔激光输出模式分布情况.结果表明,在腔长30 cm、角锥镜棱宽小于75μm、二面角误差在-10′~5′之间时,可实现光斑完整的圆形分布输出模式,且有较好的光束质量;棱宽不小于0.4 mm,二面角误差在-40′~10′之间时,光斑为TEM 03阶横模,光场呈六瓣分布;当角锥镜棱宽为0.4 mm、二面角误差为3′,腔长从30~90 cm范围内增加时,该谐振腔输出的激光模式从TEM 03转换成TEM 10.     

Diode-Side-Pumped Passively Q-Switched Mode-Locked 532 nm Laser with a Nd:YAG/Cr4+:YAG/YAG Composite Crystal

We present a diode-side-pumped Q-switched mode-locked (QML) laser operating at 532 nm for the first time employing a composite crystal Nd:YAG/Cr⁴⁺:YAG/YAG and a KTP. The experimental results show that, using a suitable cavity and crystals, one can obtain high-quality QML laser output at 532 nm with a side-pumped system. We measure and analyze the QML performance of the fundamental frequency laser and the green laser. Under a pump power of 127 W, we obtain a QML laser operating at 532 nm with an average power of 4.97 W and a repetition rate of 0.2 GHz for the mode-locked pulses; the corresponding depth of modulation is close to 100%.     

Efficient High-Power Ho:YAG Laser Pumped by Dual-End-Diode-Pumped Tm:YLF Laser

We report a Ho:YAG (Ho-doped yttrium aluminum garnet) laser pumped by a dual-end-diode-pumped Tm:YLF (Tm-doped yttrium lithium fluoride) laser to obtain an efficient experimental device with high output-power characteristics. We study the influence of the specific values of the output coupling mirror transmittance, the resonant cavity length, and the radius of curvature of the output coupling mirror on the Ho:YAG laser output characteristics. Under optimum experimental conditions, under which the output coupling mirror transmittance was 30%, the resonant cavity length was 25 mm and the output coupling mirror radius of curvature was 300 mm, and the maximum pumping power of the dual-end-diode-pumped Tm:YLF laser was 15.2 W. We obtain an efficient high-power 2.122-μm laser output of 7.98 W from the Ho:YAG laser. The optical-to-optical conversion efficiency is 52.5%, and the beam quality factor figures are M _x ² ?=?2.89 and M _y ² ?=?2.97.     

Alignment-free He–Ne laser with folded cavity

To solve out of operation induced by the disarrangement of cavity mirrors in half intra-cavity He–Ne lasers, a new structure of alignment-free He–Ne laser with folded cavity is invented. A corner cube prism (CCP) is used to structure a folded cavity. This novel laser can work conveniently without any adjustment. Both intensity curves of solid and hollow CCPs are studied, which indicate that it is a finely robust and stabile, and has a large changeable range (approximately, 60 mm) of cavity length. Bright prospect in applications improving the nanometer laser ruler invented by our group before is also shown.     

High-Power passively Q-switched 532 nm green laser by using Nd:YAG/Cr4+:YAG composite crystal

This paper reported a passively Q-switched 532 nm green laser of LD pumped V cavity structure by using Nd:YAG/Cr⁴⁺:YAG composite crystal and the type II phase matching KTP crystal. Under 19.4 W pump power, the average power of the laser pulse up to 1.83 W, with the pulse width of 93.2 ns and repetition frequency of 9.1 kHz.     

Optimization of Diode-Pumped Continuous-Wave Tape-Casting YAG/Nd:YAG/YAG-Ceramic Lasers

We demonstrate a diode-laser-pumped solid-state 1.06 μm laser using a novel YAG/Nd:YAG/YAG composite ceramics with a sandwich structure. We optimize the laser performance using different output couplers, pumping beam waists, and cavity lengths. A maximum CW output power of 11 W for the YAG/Nd:YAG/YAG-ceramic laser is obtained at an absorbed pump power of 25 W resulting in a slope efficiency of 49.4%. The excellent output performance shows that the novel YAG/Nd:YAG/YAGceramic material has a great potential in applications with diode-laser pumping.