同轴射频激励CO2激光器的热效应研究

通过求解放电等离子体中的带电粒子密度和能量的平衡方程、电流连续性方程以及热传导方程,研究了同轴射频(RF)激励CO2激光器中放电混合气体的温度效应,分析了有关放电参数对温度分布的影响。     

脉冲CO_2激光作用下光气在BCl_3中的分解与生成

研究了在脉冲能量为0.8焦耳的TEA CO_2激光作用下BCl_3中光气的分解与生成。峰值功率密度约10~6瓦/厘米~2的脉冲CO_2激光,既不引起BCl_3中COCl_2的分解,也不引起BOl_3中的CO和Cl_2生成COCl_2。在焦点区峰值功率密度约10~8瓦/厘米~2的CO_2激光,则引起BOl_3中光气的分解和生成。     

混合型TEA CO2激光器

本文给出了一种获得单纵模脉冲激光的装置。该激光器由TEA CO2和CWCO2激光器组成,采用内注入,结构简单易注入成功。本实验得到了预期的结果,并提出了进一步改进的方法。     

CO_2波导激光器的最佳化

计算了内腔封离型CO_2波导激光器的EH_11波导模的传输和耦合损耗,设计并制造了内腔封离型CO_2波导激光器.器件的最高输出功率为3.57W,单位激活长度和体积的输出功率分别为0.27W/cm、17.3W/cm~3.     

Subnanosecond multi-gigawatt CO2 laser

A semiconductor switching technique has been utilized to produce 30-300 ps variable duration CO₂ laser pulses of 0.5-MW peak power. Eight passes through a 1.2-m long, UV-preionized, 3-atm TE CO₂ amplifier raise the output laser peak power to the 10¹⁰ W level. Sampling the amplifier gain in linear and saturated regimes using CO₂ laser radiation ranging from CW to 30 ps pulse length permits comparison with computer modeling of picosecond CO₂ pulse amplification. The potential for further peak power scaling of picosecond molecular lasers is discussed     

Misalignment effects in a CO2 waveguide laser

A study is made of a CO₂ waveguide resonator with a square bore and plane mirrors focusing on the theoretical and experimental effects of changing the mirror-guide distance and of tilting the mirror. It is found that it can be misleading to neglect typical mirror-guide distances z≃2-4 mm in favor of extreme-near-field (case I) simplifications. The results from a small (≃20 cm×1.3 mm×1.3 mm) RF-excited laser agree well with predictions (from an improved multimode matrix model) of output power, line-tuning behaviour, and CW (continuous wave) beat frequency     

Hooting modes in a CO2 waveguide laser

CO₂ waveguide lasers `hoot' when, instead of the solitary resonator mode expected from a homogeneously broadened gas laser, two or more resonator transverse modes laser simultaneously on a common laser line. The unwanted mode or modes, even if very faint and present only occasionally, can impede heterodyne measurements where a clean frequency spectrum is required. The authors report measurements of transverse-mode beat frequencies from a small RF-excited CO₂ laser with a hybrid Al/Al₂O₃ square-bore waveguide and plane mirrors; these frequencies alter with mirror tilt by up to 70 MHz mrad^-1. A minimum beat frequency is seen when the laser is well assigned. The authors suggest that a model of the misaligned resonator may help to identify the faint modes responsible for hooting     

2千瓦横向流动闭合循环CO_2激光器

本文报导了千瓦级横向流动闭合循环 CO_2激光器的组成,着重讨论了无弧光放电电极结构及放电特性。采用多针触发使较大放电电流时的辉光放电稳定性明显提高;主电源直流输出特性及限流电阻选择对放电稳定性及功率输出影响很大。放电区气流速度40米/秒,工作气压46毫米汞柱,激活区长度86厘米,获得2千瓦连续多模输出,电光效率达15%。     

长寿命CO_2激光器

实验证明,要获得长寿命的 CO_2激光器的主要措施有:(1)杜绝慢性漏气;(2)电极材料的选择及氧化处理;(3)减少 CO_2:分子的分解。我们的做法是:激光管不经烘烤,并附加水蒸气,电极材料均经真空除气且充氧氧化,在采用纯银电极、气体组分分别为(1)CO_2-N_2-He-Xe-H_2O;(2)CO_2-CO-He-Xe-H_2O;(3)CO_2-N_2-CO-tte-Xo-H_2O 时,运转寿命分别达(1)10476小时;(2)9185小时(仍在运转);(3)9207小时(仍在运转)。而采用纯镍电极,气体组分为 CO_2-N_2-He-Xe-H_2O,运转寿命达1644小时。     

对CO2激光器中CO分子的分析研究

本文对CO分子在CO2激光器中所起的作用进行了分析研究,并根据实测的有关温度分布与变化曲线,提出了明确的改进措施.     

TEA CO_2激光器自由振荡输出光谱的实验研究

本文对TEA CO_2激光器的自由振荡输出光谱及时间谱进行了研究。结果表明,振荡一般为单一谱线,也有可能双谱线同时振荡,以P_(10)(20)线振荡几率最大。     

大功率CO2激光器输出窗口热性能分析

为了研究大功率CO2激光发射过程中输出窗口吸收激光能量产生热性能变化的问题,建立了输出窗口传热学和结构力学耦合非稳态模型,通过对模型进行有限元分析得到表征输出窗口变化的温度、热变形和热应力等参数分布。首先,针对大功率CO2激光特点,讨论了输出窗口材料GaAs和ZnSe的物理特性。然后,基于10 kW级大功率CO2激光器光学谐振腔结构和输出窗口材料物理特性,建立了输出窗口传热学和结构力学的有限元模型。最后,利用COMSOL软件对该模型进行求解,得到以GaAs和ZnSe为材料的输出窗口的温度、热变形和热应力等参数分布,并对比分析不同窗口材料对参数的影响。研究表明:在10 kW级激光作用下,ZnSe窗口温升小于GaAs窗口;两种输出窗口产生m量级热变形;由于GaAs材料的热导率高,GaAs窗口的热变形和热应力分布更为均匀。     

CO2激光参量上转换的研究

本文首次报道了CO2激光在AgGaS2晶体中上转换成近红外辐射的研究结果。用SPD-052雪崩光电二极管探测,获得的等效噪声功率(NEP)～3.8×10-8W,探测灵敏度(Dλ#)～1010cmHz1/2W-1。Ⅱ类非共线相位匹配的功率转换效率估计为10%。     

Atmospheric thermal lens induced by high-power CO2 laserbeams in laser materials processing

The atmospheric thermal lens induced by high-power CO₂ laser beams in laser materials processing and its influence on beam propagation and focus are studied in this paper. It is found in experiments that the atmospheric thermal lens is generated when the air in the beam propagation path is stationary. But it can be eliminated by blowing air with a certain pressure into the beam's guidance system. Also, the behavior of the beam's propagation under the case of the thermal lens deviates from Gaussian theory. This deviation is calculated by the linear and nonlinear models of the atmospheric thermal lens under the conditions of a large beam diameter and high power intensity. In addition, the influence of the thermal lens on the beam's focus size and position is also discussed in this paper     

Scaling of laser power with N2 partial pressure in aconvective-cooled CW CO2 laser

Diffusion-cooled and convective-cooled CW CO₂ lasers have significantly different N₂ partial pressure in their optimum laser gas mixture. While in diffusion-cooled lasers the N₂ fractional concentration is normally within 20% of the total gas pressure, it ranges up to 60% in convective-cooled lasers. By considering various effects of N₂ and solving a simplified rate-equation model analytically, the large difference in the optimum N ₂ concentrations in these two types of CO₂ laser is explained     

声光Q开关波导CO2激光器

用Ge单晶作为声光介质首次研制出声光Q开关波导CO2激光器,Q开关激光脉冲重复频率从0Hz到200kHz任意可调。文中对这种Q开关激光器的性能作了介绍。     

无He高速流动CO_2激光器的研究

用一个开环流动装置研究了无He混合气的放电CO_2激光输出特性,获得1400W的输出,电光效率～5％,并建立了流动条件下的分子动力学模型,分析计算了小讯号增益、气压、密度、流速、温度等参数沿流场的分布。     

CO2 laser performance with a distributed gold catalyst

The performance of a CO₂ laser was improved by coating the inside wall of the discharge tube with a discontinuous gold film. In the presence of the discharge, the gold acts as an ambient temperature catalyst to reform decomposed CO₂. The gold coated laser delivered 122 W/m for both sealed-off and flowing operation. CO₂ decomposition levels are presented as a function of input power, gas pressure, and temperature. Atomic oxygen, generated by the discharge, appears to be required for gold to exhibit any detectable catalytic activity     

高重复频率TEA CO2激光器

本文报导了一种封离式内循环高重复频率TEA CO2激光器的设计与制作,并给出了基本参数及初步实验结果.     

新型高重复频率脉冲CO2 激光器

报道了一种新型高重复频率的脉冲CO2激光器。该型激光器结构紧凑,激光器外型尺寸为300 mm300 mm300 mm,工作气体放电增益体积为12103mm3,谐振腔的长度为310 mm。为了获得大体积均匀稳定的气体放电,激光器采用了紫外电晕预电离方式。在激光器自由运转时,单脉冲激光的输出能量达到15 mJ,输出脉冲的半高全宽为70 ns。激光器采用紧凑型高速涡轮增压风机,在一个大气压的条件下,气流循环速度超过100 m/s,激光脉冲重复频率为1.5 kHz,采用大体积强迫冷却和气体主动置换技术,可以获得较长时间激光稳定输出。在已有的实验基础上,采用光栅调谐,可快速准确地实现高重复频率脉冲CO2激光器的谱线选支输出。