基于透射式非稳腔的单纵模TEA CO_2激光器

为了获得TEA CO_2激光器高质量的单纵模输出,对种子注入锁定的TEA CO_2激光器进行了研究。首先,本文提出了一种透射耦合输出的虚共焦非稳谐振腔方案,利用Glad软件的Prony法对腔模的演化进行了仿真分析,并实验记录了近场与远场的光斑光强分布。仿真结果与实验结果吻合,验证了此腔型方案的合理性。其次,在此腔型的基础上进行了腔外种子注入锁定实验,实验结果显示:自由振荡时存在频率为195 MHz的拍信号,当种子注入锁定成功后,输出激光拍频消失,波形变光滑,峰值功率降低48.6%,脉冲产生时间缩短20ns。实验结果与已有成果吻合,验证了此种透射式非稳腔的TEA CO_2激光器具有输出高质量单纵模的能力。     

LD外腔结构的传输矩阵理论分析

利用传输矩阵理论结合具体实验装置分析了外腔反馈注入系统的特性和反馈注入光束的传输特点。对准直型和会聚型两种不同的外腔结构分别进行了理论计算和比较,得出了会聚型外腔具有对外腔镜倾斜失调不灵敏的突出优点的结论。并在半导体激光器列阵的外腔实验研究中获得上述理论的验证,得到了远场分布光瓣宽度(FWHM)为0.46°,相应于光束质量为1.12倍衍射极限的激光输出。     

大功率TEA CO2激光器的电磁辐射测试及屏蔽方舱设计

为了抑制大功率TEA CO<,2>激光器对其他电子设备的电磁干扰,在测量并分析激光器的近场电磁辐射特性的基础上,设计了电磁屏蔽方舱并进行了实验验证.根据大功率TEA CO<,2>激光器的工作原理,分析了激光器工作过程中的主要电磁辐射源;结合电磁辐射理论与激光器的实际结构,确定了电磁辐射测试的主要部位为火花开关、主回路、...     

体布拉格光栅外腔倍频半导体激光器研究

为提高绿光激光器的输出特性,设计了一种体布拉格光栅外腔倍频半导体激光器。采用反射型体布拉格光栅作为反馈元件构成外腔半导体激光器,并使用三硼酸锂晶体进行倍频,研究了基频光的光束及光谱特性对倍频光的光束及光谱特性的影响。实验结果表明,使用体布拉格光栅进行外腔锁波时,所得到的倍频光同样能实现窄带宽输出,同时倍频光的远场分布与基频光的远场分布一致。使用衍射效率为10%的体布拉格光栅作为外腔输出镜,可将半导体激光器的输出波长稳定锁定在1 064 nm,所得到的倍频光波长稳定在532 nm附近,光谱线宽压缩至0.4 nm左右,输出功率可达73 mW。     

折叠式准封离型CO2激光器及其在切割和焊接中的应用

为满足激光切割、焊接对高光束质量激光器的迫切需求,开发了一种折叠式准封离型有自主知识产权的高光束质量、高稳定性、高可靠性、低消耗、长寿命千瓦级CO2激光器.目前已批量生产,成功应用于激光切割与焊接生产,打破了高光束质量激光器长期被国外产品垄断局面.     

全光纤激光器光束质量的优化

基于激光器的结构,实验研究了影响光束质量的因素。搭建了百瓦级全光纤激光器,在最大泵浦功率为436 W的条件下,在1 080 nm处获得的激光输出为300 W,光-光转换效率为69%,光束质量M²为1.13。实验研究了谐振腔出射的激光光束在传能光纤中传输时径向功率分布的变化,结果显示：随着光束在光纤中传输距离的增加,光纤中的包层光功率呈现出先增加后保持不变的趋势,因而在传输距离上选择不同的长度对包层光进行剥除,可以获得不同的光束质量。实验还显示,在相同的泵浦条件下,与包层光剥离器设置在腔外相比,其设置在谐振腔内可获得更高的激光输出功率,但是光束质量较差。最后,采用在腔内腔外各加一个包层光剥离器的方法获得了更好的光束质量,此时M²为1.07。     

瞬变电磁场辐照下液晶显示模块的电磁兼容预测

由于大功率TEA CO2激光器系统中的液晶显示模块易于耦合电磁干扰,从而影响激光器的正常工作,本文研究了在瞬变电磁场辐照下预测液晶显示模块电磁兼容(EMC)能力的方法。分析了液晶显示模块集成于激光器系统时受干扰耦合的机理;从场线耦合干扰的角度,采用Taylor形式的BLT方程对液晶显示模块耦合的场线电磁干扰进行了分析计算,并采用实验手段对预测结果进行了验证。计算结果显示:连接线缆耦合电磁场在液晶显示模块数据线上产生的干扰电压为1V,超出了电路的噪声容限,需要采取EMC控制措施保证液晶显示模块的工作性能。验证实验结果表明:得到的EMC预测的结果能够正确反映液晶显示模块的实际EMC性能。该方法对大功率TEA CO2激光器电磁辐射近场区内电气设备的电磁兼容预测与设计具有指导意义。     

半导体激光器的远场准直特性研究

对半导体激光器远场的准直特性进行了分析,并介绍了一种多激光器物镜耦合准直系统的基本结构,它可以使每个半导体激光器的能量在淮直光束的远场进行叠加,有效地提高其光子流密度,从而扩大半导体激光器的应用领域。     

射频激励板条波导CO2激光器远场空间压缩单峰输出模式的研究

从研究射频激励板条波导CO₂激光器远场压窄单峰的理论成因出发,根据实验现象,通过理论分析和数值计算得出宽波导平平腔自再现模,这种自再现模式与无波导壁时不同,其近场具有复杂分布,理论分析表明求出这种模式的远场是压窄单峰强度分布,实验结果证实了这种模式的存在.     

声光调QCO_2激光器

为满足激光测距、环境探测、空间通讯及激光与物质相互作用机理研究等领域应用要求,研制了声光调Q CO2激光器.针对影响声光调Q CO2激光器输出的各种因素,利用调Q脉冲激光器速率方程对该激光器输出的主要技术参数进行了理论分析和计算,提出了声光调Q CO2激光器优化设计的方法,并进行了验证实验.激光器脉冲重复频率为1 Hz～50 kHz, 在1 kHz运转时获得的输出激光脉冲宽度为180 ns,峰值功率为4 062 W,与理论计算基本一致.结果证明:通过声光晶体(AO)的优选及谐振腔的合理设计,可实现小型CO2激光器的高重频、窄脉宽,高峰值功率输出,并可通过光栅选线的设计方式和TTL信号控制实现此类激光器的波长调谐和编码输出.     

基于氟化镁晶体微腔产生宽光谱范围克尔光频梳及色散调控研究

为了在基于回音壁模式光学微腔的光学频率梳生成中优化微腔的性能和光频梳的质量,对氟化镁晶体微腔的色散调控进行研究.首先,理论仿真研究了MgF2晶体微腔边缘形状对腔内模场和总色散的影响;接着根据仿真结果实际加工了两种面形的MgF2晶体微腔,分别为边缘平面型和单边楔形;然后,搭建了微腔性能检测系统和晶体微腔光梳生成系统,实测...     

Repetitive operation of switchless transverse flow transversely excited atmosphere CO2 lasers

The enhanced preionisation efficiency of a mutually coupled parallel spark preioniser has been exploited to achieve switchless operation of a transversely excited atmosphere (TEA) CO(2) laser in the conventional transverse gas flow configuration. This made the laser more compatible to repetitive operation and the satisfactory performance of a switchless TEA CO(2) laser of ~8 cc active volume is reported here up to a maximum repetition rate of 100 Hz at a gas replenishment factor of ~2.     

Laser beam quality and pointing measurement with an optical resonator

We present a compact diagnostic breadboard that is based on an optical ring resonator for measuring beam quality and pointing of single-frequency continuous wave lasers at a wavelength of 1064 nm. To determine the beam quality of the coherent test beam, this optical resonator is used to perform a mode decomposition into Hermite-Gaussian modes. For our laser system, a power fraction in the fundamental Gaussian mode of 97.2%+/-0.2% was measured. Residual misalignment and mis-mode-matching to the resonator as well as the astigmatism and/or ellipticity of the test beam have been determined. Numerical simulations showed that measurements of the M(2) factor and transversal intensity distribution are not suitable for determining this power fraction. To measure the beam pointing, the fundamental mode of the optical resonator was used as a stable reference. The pointing of the test beam was measured with the differential wave front sensing technique up to Fourier frequencies of 1 kHz with a sensitivity to relative pointing of /epsilon/=1x10(-6)/sqrt[Hz]. Pointing measurements with an alternative method were performed and showed good agreement.     

Digital feedback stabilization of a single-axial-mode CO2 TEA laser

We have achieved long-term stability in producing high-power single-axial-mode CO2 laser pulses with a hybrid oscillator (TEA laser + low-pressure section) by using a novel digital feedback system that electronically adjusts cavity length.     

Use of 13CO2 in high-power pulsed TEA lasers

The use of 13CO2 in carbon dioxide lasers enhances the available spectral range very significantly but is prohibitively expensive if gas flow through the laser is required. A TEA CO2 laser equipped with a gas recirculation system is described. This reduces gas costs to negligible levels even for expensive isotopic mixtures.     

A piezoelectric resonator for optical power measurement with radiation beam quality retaining

A method for measuring the power of laser radiation in a wide range of wavelengths is introduced. The method is based on weak heating of an optically transparent piezoelectric resonator through which laser radiation is transmitted. After passing through such a resonator, the beam quality of laser radiation remains unchanged and the optical power can be utilized in laser technologies.     

9.3微米脉冲激光激光倍频实验

本文介绍了利用9.3m脉冲TEACO2激光通过AgGaSe2晶体二次谐波产生（SHG）技术实现4.65m中红外波段激光输出的实验研究。根据非线性光学技术原理和倍频技术的基本要求,通过有针对性的技术手段对于TEACO2激光器实现输出谱线选择和脉冲波形时间分布整形控制,使之尽量满足激光倍频试验对于泵浦的脉冲光源在波长和输出时间分布上的基本要求,并以此作为基波光源进行了产生二次谐波的试验研究工作。实验结果显示,即使是相同的AgGaSe2倍频晶体材料,由于生产厂商的不同具有完全不同的表面破坏阈值行为,而相同点是体损伤阈值均大于表面损伤阈值。实验上获得倍频输出最大能量12.9mJ;倍频输出最高平均功率940mW。     

CO2 laser pulse shortening by laser ablation of a metal target

A repeatable and flexible technique for pulse shortening of laser pulses has been applied to transversely excited atmospheric (TEA) CO(2) laser pulses. The technique involves focusing the laser output onto a highly reflective metal target so that plasma is formed, which then operates as a shutter due to strong laser absorption and scattering. Precise control of the focused laser intensity allows for timing of the shutter so that different temporal portions of the pulse can be reflected from the target surface before plasma formation occurs. This type of shutter enables one to reduce the pulse duration down to ~2 ns and to remove the low power, long duration tails that are present in TEA CO(2) pulses. The transmitted energy is reduced as the pulse duration is decreased but the reflected power is ~10 MW for all pulse durations. A simple laser heating model verifies that the pulse shortening depends directly on the plasma formation time, which in turn is dependent on the applied laser intensity. It is envisaged that this plasma shutter will be used as a tool for pulse shaping in the search for laser pulse conditions to optimize conversion efficiency from laser energy to useable extreme ultraviolet (EUV) radiation for EUV source development.     

High-energy optically pumped molecular lasers in the 13- and 16-microm regions

This paper describes the construction of an optically pumped laser device. The device utilizes a line-tunable CO2 TEA laser as a source to optically pump a cell which is capable of cooling candidate laser gases down to approximately 150 degrees K. Laser outputs of 750 mJ in the 13-microm region and 100 mJ in the 16-microm region are obtained by pumping NH3 and CF4 respectively with 10 J of CO2 laser radiation. The measured conversion efficiencies are 15% for NH3 and 3% for CF4. These lasers can be used to photodissociate polyatomic molecules and are attractive sources for practical laser isotope separation.