铜蒸气激光器振荡-放大系统的实验研究(二)

以非稳腔为振荡器谐振腔,比较了振荡器、行波放大和注入振荡放大几种方式运转的铜蒸气激光器输出光束的功率和方向性,实验结果表明注入振荡放大是最佳的结构,其效率比振荡器高30％,方向性提高的倍数(4.5倍)与几何光学的预计大致相符。     

铜蒸气激光器光束方向性与它所泵浦的染料激光器的效率的关系

实验结果表明,当铜蒸气激光的发散角从8mrad改善到1mrad,它所泵浦的染料激光器的输出功率提高一倍多.这个结果与文中给出的几何光学分析是一致的.由此可见,作为泵浦光源的铜蒸气激光器采用注入锁定非稳腔结构最为合适.     

Self-mode-locked unstable resonator copper vapor laser

We have studied a copper vapor laser equipped with unstable resonator optics and an intracavity beam splitter. The magnification of the present resonator configuration is as high as 60, and single transverse mode operation is practically supported in this system. We report on the laser output with near diffraction-limited beam divergence and a new observation of self-mode-locking behavior in the output pulses     

Fast optical shuttering and wavelength selection in copper vapor lasers and copper bromide lasers by intracavity polychromatic acoustooptic modulation

We propose a fast effective intracavity technique for optical shuttering and wavelength selection in copper vapor lasers and copper bromide lasers by inserting a polychromatic acoustooptic modulator in a low-intensity section of a classical negative branch unstable resonator. Single-pulse or multiple-pulse operation in one- or two-wavelength emission was achieved in a CuBr laser system. The spatial distributions of the output laser beam as recorded by a CCD camera showed neither power losses nor worsening of the beam quality in comparison with the classical scheme without the modulator. The laser output was characterized with a high degree of linear polarization.     

铜蒸气激光器种子注入光腔的参数计算

用矩阵光学理论计算了由主振荡器和功率放大器组成的种子注入光腔。主振荡器光腔是由曲率半径R1=-250mm,R2=5000mm,相距L=2375mm的球面镜组成的正支非稳腔;功率非稳腔是由曲率半径R3=400mm,R4=5600mm,相距S=3000mm的球面镜构成的负支非稳腔。理论计算表明,该种子注入光腔可输出光束发散角约几十微弧的激光,可满足铜蒸气激光器主振荡器功率放大器(MOPA)的技术要求。     

注入锁定铜蒸气激光器的时空、能量以及偏振特性

采用P分量的偏振光注入到平行平面腔的铜蒸气激光器中,结果表明,与未加注入光时的振荡器比较,注入锁定铜蒸气激光器的输出功率提高了43％,P分量的偏振度从0.30提高到0.78,脉宽由36ns加宽到48ns,输出光的发散角显著改善,由7.8mrad降到1.1mrad,与注入光束基本相同。     

A copper “HyBrID” laser of high-beam quality using anaxial unstable cavity

A 100 W copper “HyBrID” laser (CuHBr laser) fitted with an unstable cavity is examined in the far field and compared with a conventional copper vapor laser of similar beam dimensions. In the far field the divergence is about 100 μradians for the HyBrID laser. The copper vapor laser produces a slightly larger central divergence with significant high divergent structure. This is explained to be due to pulse shape and differences in radial variations of the gain onset timing of the two types of laser, improved beam quality is important for efficient pumping of titanium sapphire lasers and micromachining     

高功率二极管泵浦固体激光谐振腔的进展和分析

对近年来用于高功率二极管泵浦固体激光器的新型光腔，如棒成象非稳腔，近共心非稳腔，折迭腔以及ＳＢＳ相位共轭ＭＯＰＡ系统等进行了深入的分析，并对实现高功率输出和高光束质量的相关技术作了讨论。     

激光二极管抽运的主振荡级与功率放大器结构Nd∶YVO4激光器

为了实现固体激光器高功率、高光束质量的输出,设计了一种激光二极管(LD)阵列抽运的主振荡级与功率放大器(MOPA)结构的Nd∶YVO4激光器。该激光器的振荡级采用平-平谐振腔结构,并使用棱镜组对激光二极管阵列的抽运光整形,消除了激光二极管阵列抽运光不对称对振荡器输出光束质量的影响,在连续工作条件下获得了6.1 W的激光输出,其光束质量M2因子为M2x=1.14,M2y=1.13,光-光转换效率为25.6%。放大级采用具有近共焦、非稳腔特点的折叠光路结构,使振荡级激光光束10次通过放大级晶体,并且有效地抑制了放大自发辐射(ASE)和寄生振荡。在振荡级以6.1 W注入放大器时,得到最大输出功率26.8 W,此时放大器提取效率为29.1%,输出光束质量M2因子为M2x=2.08,M2y=1.92。     

高功率二极管泵浦固体激光谐振腔的进展和分析

对近年来用于高功率二极管泵浦固体激光器的新型光腔,如棒成象非稳腔,近共心非稳腔,折迭腔以及SBS相位共轭MOPA系统等进行了深入的分析,并对实现高功率输出和高光束质量的相关技术作了讨论.     

High power efficient dye amplifier pumped by copper vapor lasers

An extensive study has been performed on a dye amplifier pumped by copper vapor lasers. The amplifier utilizes a transverse pumping configuration in which the dye flow, pump beam, and dye extraction beam are mutually orthogonal. The operating characteristics of the amplifier have been studied using four dye-solvent systems which span the wavelength range continuously from 560 to 690 nm. Optimum conversion efficiencies of 18-30 percent at output powers of 0.41-0.76 W have been measured from the four dyes at a 6 kHz pulse repetition rate. The efficiencies and output powers were limited only by the available copper laser pump power. Analytic expressions have been obtained for the amplifier power gain and efficiency using a rate equation treatment of the system dynamics. Excellent agreement is obtained between the predicted and measured amplifier gain characteristics for rhodamine 6G.     

自滤波振荡行波放大的铜激光系统

采用自滤波振荡，腔内起偏，行波放大的铜激光系统，获得了发散角接近衍射极限，偏振度为９７％，绿光输出功率为８．８Ｗ的铜激光，并与非稳腔振荡行波放大的铜激光系统进行了比较。     

内腔式KTP OPO发散角的实验研究

实验研究了非临界相位匹配 (NCPM)的内腔式KTP光学参量振荡器 (OPO)的光束发散角与OPO谐振腔参数的关系。证明了望远镜型共焦非稳谐振腔是压缩OPO光束发散角的有效方法。     

A 1.4-kJ solid-state power oscillator with good beam quality

By using three 6-disk amplifiers of 10 cm clear aperture from the Nova laser as the active element in an unstable resonator of magnification M=3, we achieved a single shot output of 1.4 kJ in a beam which contains 90% of its energy within twice the theoretical beam divergence. We show that most of the beam quality degradation comes from about one wave of beam tilt during the pulse and that the tilt corrected beam quality corresponds to a Strehl ratio of ≈0.6     

含热透镜多元件谐振腔的动态工作特性

由于光泵浦热效应,高功率固体激光器的输出参数如光束远场发散角、输出功率等会发生变化。本文使用g-参数等价腔详细研究了各种类型稳定腔、临界腔的动态工作特性,例如g-参数图上工作点的运动规律、临界光焦度、临界g参数以及光斑半径、远场发散角等。文中还对理论的实验验证和应用进行了讨论。     

Enhanced efficiency of UV second harmonic and sum frequencygeneration from copper vapor lasers

The authors have generated over 460-mW output power at 255.1 and 271.2 nm with a wall-plug efficiency of 0.016% and 300 mW at 289.1 nm with a wall-plug efficiency of 0.0008%. Using an off-axis unstable resonator matched to the plasma-tube geometry and gain characteristics along with focusing lenses with reduced achromatic and spherical aberration has allowed the highest efficiencies for nonlinear UV generation from a CVL (copper vapor laser) reported to date. Current UV output powers are limited by crystal damage which may be reduced by modifying the delivery optics     

掺杂稀土光纤激光器与激光放大器(续篇)

(1)美国贝尔做出的光纤放大器实验。掺铒光纤,芯径:5μm,数值孔径:0.18,掺杂:1.8×10~(18)铒离子/cm~3,泵光吸收为2.5dB/m,信光吸收为4dB/m,输入光信号为15μW(1.53μm),泵光功率为20、55、100mW(0.52μm)。由此得到的室温下增益为22dB。20mW泵浦时最佳长度为7.5m(增益为10dB)。图14是得到的主要测量曲线,从中不难看出,在高功率泵浦时,增益将出现饱和。     

高平均功率铜激光振荡放大系统

从铜蒸气激光器的特点出发, 扼要概述在设计具有光电控制的振荡放大链工作中所需注意的若干问题, 包括振荡源的选择、空间滤波、放大器的延时与同步控制、热透镜的影响与补偿以及偏振问题等。     

Design and performance of high-gain free-electron lasers withgrazing incidence, unstable ring resonators

Grazing incidence, ring resonators have been proposed for high-grain free-electron lasers to alleviate the problem of inordinately high irradiance on intracavity optics. Such resonators are also relatively compact, and consequently, their alignment tolerances are more manageable. A geometric design algorithm and detailed computer analysis of a high-gain free-electron ring laser with hyperboloid-paraboloid grazing incidence telescopes is presented. A 3-D wave optics computer code is used to determine the loaded-cavity transverse-mode characteristics of the high-gain unstable ring and to examine the issue of transverse-mode control as a function of the key resonator parameters. Perturbation sensitivity of the individual elements is also determined and compared to that of a corresponding long stable resonator     

TEA CO2激光器同轴非稳腔光束质量

TEA CO2激光器作为推进系统的理想新能源之一,在提高单脉冲能量的同时,为了保证远距离传输效率,必须对其光束质量提出适当要求。通过漫反射法及分光束法精确测量了1Hz下TEA CO2激光器在平-凹型稳定腔和改进的带有涡流管冷却系统的同轴非稳腔的光束发散角,在得到稳腔β=12.53的情况下,采用改进后的同轴非稳腔,β=3.28,且单脉冲能量损失很少。这一结果对继续研制激光推进系统中大体积高能TEA CO2激光器是很有帮助的。