Oxide-confined vertical-cavity surface-emitting laser pumped Nd:YVO4 microchip lasers

In this letter, we demonstrate an experimental study of using a large area oxide-confined vertical-cavity surface-emitting laser (VCSEL) to pump a Nd:YVO₄ microchip laser. The maximum output power of 1.2 mW in TEM₀₀ mode is obtained with a pump power of 8.2 mW. Experimental results show that the complex transverse modal behavior of VCSELs in the higher injection current may cause an impediment of power scaling     

Efficient, scalable, internally folded Nd:YAG laser end-pumped bylaser diodes

A scalable diode-pumped Nd:YAG laser is described in which the gain element resembles a penta-prism. This design allows longitudinal pumping along five separate axes. Using five high-power single stripe laser diodes, 4.16 W of absorbed power produced 2.3 W CW at 1.06 μm. The slope efficiency was 56%, the output was plane polarized, and the laser operated in the TEM₀₀ mode. The threshold power, was 48 mW. No evidence of thermal saturation was observed up to the maximum pump power. With an intracavity KTP crystal, 431 mW of CW amplitude-stable output at 532 nm was generated. Repetitive Q-switched operation is also reported     

LD泵铺Nd：YVO4／Cr：YAG被动调Q绿光激光器

报道了一种LD近贴泵浦、KTP晶体腔内倍频的Nd:YVO4/Cr:YAG结构高重复频率被动调Q绿光激光器。在注入泵浦功率为750mW时,得到平均功率86mW、脉冲宽度26.6ns、重复频率79.2kHz、峰值功率41.1W的被动调Q脉冲绿光输出。     

激光二极管抽运Nd∶YVO4/YVO4复合晶体激光器

在高功率激光二极管(LD)抽运的情况下,对比分析了Nd∶YVO4/YVO4复合晶体和Nd∶YVO4单一晶体的激光特性。实验证明,复合晶体能够有效地降低晶体内的温度梯度,减小由端面变形带来的热透镜效应,获得比单一晶体高出许多的输出功率。采用Z型折叠腔,研究了Nd∶YVO4/YVO4复合晶体KTP倍频特性,当抽运功率为17W时,获得了6.23W的绿光输出,抽运光到绿光的转换效率高达37%。     

Nd:YVO4自锁模皮秒激光器

设计并研究了Nd:YVO4自锁模皮秒激光器,探究了激光器的最佳锁模条件。观察并分析了自锁模皮秒激光器准周期锁模、倍周期锁模状态,研究并测量了结构紧凑的直腔自锁模激光器的输出特性。谐振腔为凹平直腔,Nd:YVO4晶体作为激光增益介质和克尔介质,在未加其他锁模元件的情况下,实现了1 064 nm高效率连续锁模脉冲激光输出。晶体距输入镜16 mm、腔长为90 mm时,对1 064 nm透过率分别为10%、20%、30%和50%的四种输出镜下激光器的输出特性进行了对比分析。对激光器进行优化设计,输出镜透过率为10%,泵浦功率为8 W时,激光器输出功率为2.76 W,斜效率高达43.2%,锁模脉冲重复频率为1.43 GHz,激光器实现了高效、稳定的连续锁模。     

LD抽运Cr4+:YAG被动调Q c-cut Nd:YVO4自拉曼激光器

对激光二极管(LD)抽运的Cr4+:YAG被动调Q c-cut Nd:YVO4自拉曼激光器进行了实验研究。通过采用不同初始透射率的Cr4+:YAG和不同反射率的输出镜进行实验,研究了初始透射率和反射率对拉曼光输出特性的影响。测量了拉曼光的平均输出功率、脉冲重复频率和脉冲宽度随抽运功率的变化。在抽运功率为4.8 W时,拉曼光的最高平均功率为370mW,相应的光-光转换效率为7.7%。实验中得到了亚纳秒级的拉曼光输出,最高单脉冲能量为54μJ,最高峰值功率为47kW。     

大功率激光二极管端面抽运的Nd：YVO4激光器

报道了利用掺杂浓度为0．3at．-％，通光长度为10mm的Nd：YVO4晶体作为增益介质，带光纤耦合的激光二极管端面抽运的Nd：YVO4激光器。在抽运功率为27．365W时，获得了14．85W的TEM00模输出，光-光转换效率为60．49％，斜率效率达64．5％。在上述基础上对晶体的掺杂浓度和晶体长度对激光器性能的影响进行了分析。     

半导体泵浦双通Nd:YVO4板条激光放大器

报道了一种高效率、结构紧凑型半导体泵浦Nd:Y VO₄板条激光放大器,主振荡器为被动调Q微片激光 器,在重复频率20kHz时,种子激光为平均功率为0.5W、脉冲宽度为2.43ns的基模激光。设计了分别针对泵 浦光和种子激光进行整形的激光放大器,匹配泵浦光模体积,实现高的能量提取效率和高增 益放大,并减 小热透镜效应。采用柱透镜对半导体激光器单bar发射的泵浦光进行整形,采用焦距为60mm的柱透镜, 对一通种子激光进行整形匹配泵浦光的模体积,采用焦距为75mm的 球透镜构成一组相传递系统,使二通 种子激光匹配泵浦光的模体积。在重复频率20kHz时,实现了平均功 率为6.3W、脉冲宽度 为2.52ns和光束质量M²为1.5的激光输 出,能量提取效率大于16%。     

Efficient high-power diode-end-pumped TEM00 Nd:YVO4 laser

We demonstrate a compact and efficient diode-end-pumped TEM₀₀ laser with output power of 25.2 W for 52 W of incident pump power by use of a single YVO₄ crystal with a Nd concentration of 0.3 at.%. In Q-switched operation 21-W of average power at a pulse repetition rate of 100 kHz and ~1.1-mT pulse energy at a pulse repetition rate of 10 kHz were produced. At 10 kHz, the pulse width is around 10 ns and the peak power is higher than 100 kW     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave （CW） 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd： YVO4 and using LBO as the intra-cavity SHG crystal. With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457 nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the output power is better than 1.2% for 8 h continuously working.     

77 GHz soliton modelocked Nd:YVO4 laser

An Nd:YVO₄ laser which was passively modelocked at the very high repetition rate of ~77 GHz, using a semiconductor saturable absorber mirror (SESAM), is demonstrated. The soliton-like pulses are well separated in time and their duration is 2.7 ps. The required negative dispersion is introduced by a GTI-like structure, which is formed by the gain medium and the SESAM     

全固化环形单频Nd:YVO4可调谐激光器

分析了Nd:YVO4激光晶体两平-平通光面自身的标准具效应对单频激光器调谐特性的影响.采用一通光面切成1°劈形的Nd:YVO4晶体来消除自身的标准具效应,通过调节插入谐振腔内的标准具,使半导体激光器(LD)抽运Nd:YVO4单频激光器的最大可调谐范围达到约100 GHz.     

Influence of KTP length on the performance intracavity frequencydoubled diode-pumped Nd:YVO4 lasers

We demonstrate an experimental study of the influence of potassium titanyl phosphate (KTP) length on the performance of intracavity frequency-doubled diode-pumped Nd:YVO₄ lasers operating in continuous-wave (CW) mode and passive Q-switch mode. Theoretical and experimental results show that the optimum KTP length for CW mode is determined by the nonlinear coupling and walkoff effect and the highest optical conversion efficiency in CW mode is nearly 30% with a 10-mm KTP. On the other hand, a 2-mm KTP crystal, which is sufficient for efficient internal second-harmonic generation in a passive Q-switch mode, yield the highest peak green power of 240-W     

激光二极管抽运Cr^4＋：YAG被动调Q Nd：YVO4激光器的实验研究

对激光二极管(LD)抽运的Cr^4 ：YAG被动调Q Nd：YVO4全固态激光器进行了实验研究。着重研究了抽运功率，Cr^4 ：YAG晶体的初始透过率及其在激光腔中的位置等因素对激光器输出脉冲宽度和重复频率等性能的影响，并对实验结果进行了相应的分析讨论，在理论上加以合理的解释。     

500 kHz波长锁定878.6 nm LD双端泵浦Nd:YVO4声光调Q激光器

报道了一种由波长锁定878.6 nm LD双端抽运Nd:YVO4声光调Q激光器,重复频率在500 kHz时具有稳定的1 064 nm脉冲激光输出。在重频为100 kHz,晶体吸收功率58 W时,获得18.2 W的1 064 nm激光输出,光-光转换效率为31.3%,脉宽为15.2 ns;在重频为500 kHz、晶体吸收功率58 W时,获得26.1 W的1 064 nm激光输出,光-光转换效率为45%,脉宽为44.2 ns,重频在100~500 kHz下具有稳定的脉冲输出,光束质量较传统模式下有明显提高,并且转换效率也有提升。实验表明:利用波长锁定878.6 nm激光二极管直接泵浦的方式,有利于降低晶体热效应、提高光束质量,提高光-光转换效率,获得窄脉宽的脉冲激光输出,并且在一定的温度变化范围内具有极好的温度稳定性。     

脉冲半导体泵浦掠入射Nd:YVO4板条振荡器储能优化

板条放大器中寄生振荡的存在严重影响了激光放大器的效率,降低了板条晶体的储能。为抑制掠入射板条寄生振荡、提高晶体储能,对掠入射板条放大器的增益介质Nd:YVO4晶体进行了表面处理。该处理用离子溅射的方法,对板条的上下两个梯形面和梯形长边所在的矩形面镀锗,抑制板条内部的寄生振荡。通过实验对镀锗和未镀锗板条振荡器的自由振荡输出和调Q输出特性进行了对比,镀锗板条振荡器在调Q下的阈值电流降低了15%,晶体的储能提高了86.9%;而两种板条在调Q条件下输出的光束质量、脉宽大小、光斑形状基本一致。实验结果表明,板条表面镀锗是抑制其内部寄生振荡、提高储能的有效方法。     

1.35 GHz线性调频Nd:YVO4激光器

报道了808 nm连续半导体泵浦全固态Nd:YVO4线性调频激光器实验研究。利用优化谐振腔长度、腔内插入倾斜标准具,采用温度控制、机械减震和隔绝外部环境等稳频操作,实现了稳定的1 064 nm单频激光输出,最大输出功率140 mW。利用法柏干涉仪观察单频输出,并利用刀口法测量得到的基模高斯光束质量M2为1.05。在谐振腔内插入RTP电光晶体并连接外部高压电源,通过线性电光效应改变谐振腔长度以及改变标准具倾斜角度避免腔长调节过程中的模式跳频,实现了1.35 GHz的稳定线性调频激光输出。编程控制高压电源给RTP晶体施加幅值为2 200 V的锯齿波形电压,实现了频率20 Hz,平均输出功率为85 mW周期性的调频信号输出。     

可调谐全固化折叠腔单频倍频Nd:YVO4激光器

采用三镜折叠腔,使用KTP晶体进行内腔倍频,在激光谐振腔内插入标准具,利用标准具的选模调谐特性和激光晶体自身的标准具作用,设计并研制了LD抽运连续内腔倍频可调谐Nd:YVO4全固化激光器,实现了稳定的单频绿光输出,抽运功率1.5W时最大单频绿光输出40mW,频率可调谐范围约200GHz.     

三明治腔结构的Nd:YVO_4激光器

报道了一种三明治腔结构（Ｓａｎｄｗｉｃｈ－ｔｙｐｅｒｅｓｏｎａｔｏｒ）的ＮｄＹＶＯ４全固态激光器。用发射波长８０６ｎｍ的光纤耦合二极管激光器（ＬＤ）泵浦ＮｄＹＶＯ４晶体，泵浦光功率为７Ｗ时获得１．０６４μｍ连续波（ＣＷ）ＴＥＭ００模最大输出功率为３．７Ｗ，光学斜效率为６２％；将ＫＴＰ放入腔内倍频，当泵光为５．６Ｗ时，获得ＣＷ绿光输出６２０ｍＷ。光－光转换效率达１１％。     

Simultaneous Q-switching and mode-locking in a diode-pumped Nd:YVO4-Cr4+:YAG laser

Parametric studies of passive Q-switching and mode-locking in a Nd ³⁺:YVO₄-Cr⁴⁺:YAG laser were theoretically carried out. Simultaneous mode-locking and Q-switching was also experimentally studied. It was found that over 90% of the output power could be mode-locked in a diode-pumped passively Q-switched Nd³⁺:YVO₄-Cr⁴⁺:YAG laser. The average pulse duration of the mode-locked pulse train was estimated to he around 110~150 ps. The highest peak power of a single pulse near the maximum of the Q-switched envelope was greater than 100 kW