氦-镉激光器功率稳定性的研究

激光在应用中通常要求输出功率稳定,但是,一般的激光器稳定性能不好,较好的氦-氖激光器也有百分之几的功率漂移,有的达10%左右.因此,改善激光器的功率稳定性能是激光应用的需要.蒸气激光器在均匀轴向磁场作用下,激光的输出功率有所增加,因此可以用控制轴向磁场反馈的方法加以稳定.这一方法自然也可以用于离子激光器.磁场负反馈方法可使功率漂移较小的蒸气激光功率稳定在     

日本制成室温半导体激光器

据日本电气公司透露,该公司所属的中心研究室已于1970年10月中旬制成室温连续运转的双异结半导体激光器。目前输出功率约为几十毫瓦,估计将来可以达到100毫瓦。效率在到2%之间,但有可能增加一个数量级。响应时间小于1毫微秒。输出波长范围从8,400埃到9,200埃。     

不均匀磁场中的氦镉激光

本文研究在不均匀磁场中He-Cd激光功率的增加。实验使用了二个器件。一是放电长度为140厘米的外腔结构的大功率He-Cd激光器;另一是放电长度为72厘米的内腔结构的器件。用永久磁铁产生不均匀磁场,每块磁铁长5.6cm。磁铁离毛细管轴8毫米,相互间隔2cm轴向排列。轴向及横向磁场峰值分别为100高斯及17高斯,呈周期性变化。磁场分布采用NS-SN-NS结构。管A在放电电流160mA及较高镉浓度时,不均匀磁场使4416A激光输出增加40％以上,达100毫瓦,而在阈值附近可增加100％以上。另外,也发现不均匀磁场使3250A激光增加更     

2660埃激光的产生及应用

强紫外激光有着广泛的应用前景,利用倍频技术产生紫外激光是重要的途径之一.我们进行了钇铝石榴石激光器倍频技术的研究,用KDP和ADP两块非线性晶体进行两次倍频,把1.06微米波长的红外激光转换成2660埃波长的紫外激光,其总的能量转换效率大于5%,2660埃激光的峰值功率大于3兆瓦,重复频率10次/秒.此激光器用于育稻种和辐照链霉素优选菌种取得明显效果,在其他方面,应用潜力也很大.     

内腔式He—Ne激光偏振特性的研究

本文比较全面地论述了内脏式6528埃He—Ne激光的偏振特性.文中首先介绍了各种同腔长He—Ne激光器输出光的偏振特性以及在均匀轴向磁场下的偏振特性.进一步从理论上证明了单模线偏振以及相邻纵模正交偏振的一般规律,定性解释了多纵模激光器中相邻纵模平行偏振的特性.对于在均匀轴向磁场下的偏振特性也作了理论分析.最后,还分析了内腔He—Ne激光器在横向磁场下激光的偏振特性.     

激光-电弧复合焊接临界速度规律研究

为了加深对激光-惰性气体熔化极电弧(MIG)复合焊接特性的认识程度,采用厚4 mm的Q235低碳钢系统研究了激光功率、电弧电流和坡口间隙对复合焊接临界速度的影响规律.结果表明,激光功率、电弧电流和复合焊接临界速度成正比关系.激光功率是决定卜临界速度Vmax的主要因素,电弧电流是决定下临界速度Vmin的主要因素.增加坡口间隙能同时提高Vmax和Vmin但其对Vmin的影响更显著.在实验范围内,坡口间隙对Vmax和Vmin的最大提高幅度分别可达20%和35%.此外,激光功率越大,复合焊接可选速度范围ΔV越大.在既定激光功率下,增加电弧电流会减小ΔV.     

微晶玻璃He-Ne激光管

根据影响 He-Ne 激光功率稳定性的因素,首次采用了透明微晶玻璃管作为外壳,可切削微晶玻璃作为反射镜调节头,管子为半外腔式同轴型结构。获得6328埃、1.15微米和3.39微米三种波长的激光输出,功率稳定性≤2%/2小时。     

RF激励CO2激光器功率控制器

描述了小型RF激励CO2激光器的功率控制器设计、功能和应用,根据脉宽调制原理可以方便地把激光功率从1%变化到100%.     

电磁复合场驱动激光减材直接成型V型槽形貌研究

研究了电磁复合场对激光减材加工V型槽形貌的影响。在激光减材过程中同时施加稳态电场与稳态磁场,以获得定向洛伦兹力,从而驱动熔池排溢;通过实验研究了激光参数以及电磁场参数对V型槽形貌的影响规律。实验结果显示：在电磁复合场环境下通过改变激光参数得到了角度范围为34.82°～65.20°、深度范围为1719～5667μm的V型槽;角度随着激光功率的增加和扫描速度的降低而减小,深度随着激光功率的增加和扫描速度的降低而增大;当激光功率为1800 W时,随着磁感应强度从0 mT增大至1200 mT,V型槽底部的重熔层厚度从764μm下降至42μm;材料去除效率主要受激光功率的影响,并随着激光功率的增加而增大。加工出的目标V型槽的角度公差等级为精密（f）,深度线性公差等级为中等（m）,表面粗糙度Ra值为22.4μm。稳态磁场与稳态电场所提供的向上的洛伦兹力克服重力及表面张力驱动熔池向上流动,熔体以多次飞溅的形式脱离基体,实现一次直接成型V型槽。     

黑体泵浦CO_2-CO,N_2O-CO,CO_2-H_2O和N_2O-H_2O激光的研究

本文对黑体辐射泵浦CO_2激光和N_2O激光由于CO和H_2O的加入所引起的激光功率变化进行了理论和实验研究.CO的加入可使的N_2O激光功率增加28%.     

Power enhancement in argon II narrow-tube lasers due to zeeman effect by a transverse magnetic field

The role of the Zeeman effect for the power enhancement of a small-bore argon ion laser (488.0 nm) by applying the transverse magnetic field has been investigated both experimentally and theoretically. The σ-polarized laser has a larger output power than the π-polarized laser in the wide range of magnetic field strength. Specifically, at weak magnetic fields, enhancement occurred only for the σ-polarized laser. The experimental results are interpreted in terms of the semiclassical theory of the Zeeman laser. A narrow spectrum envelope is observed in the σ-polarized laser. In the case of internal mirrors without Brewster window, it is demonstrated experimentally that π and σ polarization coexist and compete with each other.     

An investigation of the effect of an axial magnetic field on the He-Cd+laser

The drastic effect that a weak axial magnetic field can have upon the output of an He-Cd+ metal vapor laser is reported. A 37-percent increase in output power has been observed for a tube current of 55 mA and magnetic field strength of 70 G. Also described are parametric and spectroscopic studies performed to elucidate the cause of the large power output change.     

强场物理中超热电子的产生及输运

在100TW超短脉冲钛宝石激光装置上完成了飞秒激光-固体靶相互作用中超热电子的产生及输运特性的实验研究。获得了超热电子的能谱、产额、注量和总能量。结果表明,随着功率密度的增加,靶前法线方向的超热电子更容易产生;超热电子的注量和总能量随靶厚度的增加而减少。超热电子约80%的能量主要沉积在靶内的前10μm,分析表明,这主要是静电场的影响所致。     

Equivalent dipole moment method to characterize magnetic fields generated by electric appliances: extension to intermediate frequencies of up to 100 kHz

A previously proposed simple method to characterize magnetic fields near electric appliances was extended to intermediate frequencies of up to 100 kHz. The method consists of identification of the magnetic dipole moment that is equivalent to a magnetic field source of an electric appliance and simple estimation of the magnetic field distribution around the appliance. In addition, frequency characteristics of the magnetic field were taken into account by considering the harmonic components in the magnetic-field waveform for both power frequency and intermediate frequency ranges. For the application of the method, a wide-frequency range (from power frequency to 100 kHz) magnetic-field measuring instrument was developed and applied to appliances that generate intermediate frequency magnetic fields, i.e., an induction heating cooker, a TV set, and a metal detector. The results revealed that the method is adequate to quantify the magnetic field near the electric appliances at frequencies of up to 100 kHz.     

Powerful millimeter-wave generators based on the stimulated Cerenkov radiation of relativistic electron beams

Effective relativistic Cerenkoy generators of various types were studied experimentally: orotrons, surface wave oscillators, and Smith-Purcell free-electron masers that were first realized. Single-mode generation was obtained in multimode systems using electrodynamic and electron methods of mode selection. The power obtained in this regime was 100 MW at 8.6 mm with the efficiency 10%, 50 MW at 5.5 mm with the efficiency 5%, and 8 MW at 2.4 mm with the efficiency 3%. In a multimode regime the power of 0.5 MW was obtained at 0.9 mm. The study of the dependence of the generation power on the value of the focusing magnetic field revealed the presence of zones of cyclotron power absorption, that were earlier observed in centimeter-wave generators.     

8C1--The laser current transformer for EHV power transmission lines

A current measuring device applicable to an extra-high voltage power transmission line higher than 500 kV is proposed with preliminary experimental results. It obtains the instantaneous magnetic field ajacent to a transmission wire by measuring the angle of Faraday rotation of a laser beam in a flint glass rod. The laser beam is transmitted and analyzed at a ground potential site, and in the energized part this device has neither insulated conductors nor active elements. An experimental laser current transformer yielded a sensitivity of 66 mV per 100 A and good linearity. Various sources of error and modifications are discussed.     

A 100 kW, 140 GHz pulsed gyrotron

The design and operation of a 100 kW, 140 GHz pulsed gyrotron are reported. To our knowledge, this is the highest frequency at which high gyrotron output power (>-100 kW) has been achieved. Results are presented for gyrotron operation in the range of magnetic field from 4 to 7 T, voltage from 23 to 80 kV and current up to 7.5 A. Near a value of magnetic field of 5.4 T, and output power of 100 kW was obtained at 140.4 GHz in single mode operation in the TE₀₃₁ resonator mode.     

SiCp/Al复合材料厚板皮秒激光制孔重铸层影响研究

为了探究激光加工高体积分数碳化硅颗粒增强铝基(SiCp/Al)复合材料厚板的成孔特征,采用激光旋切法对厚度为4mm的SiCp/Al复合材料进行直径为1mm的制孔实验,分析紫外皮秒激光制孔中重铸层及其表面裂纹的形成机理,获得了关键激光加工参数(激光功率百分比和扫描速率)对孔重铸层的影响规律.结果表明,SiCp/Al复合材...     

一种可调的全密封大功率氦-氖激光管

本文介绍一种采用玻璃封接工艺制作的全密封大功率氦-激光管。该管系全内腔可调结构，腔长1米，在不同加磁场，不用氦-3的条件下，可在6328A输出40mW以上的多模功率，寿命可保用三年。     

Intrinsic gigahertz modulation of photolytic iodine lasers

A photolytic iodine laser is shown to have a 13.59-GHz modulation in the laser radiation when simultaneous lasing of two hyperfine transitions is obtained. The necessary gain tuning required to achieve dual-line lasing is accomplished through the use of a magnetic field. In addition, we investigate the possibility of using a nonlinear mirror to increase the gain coupling between the two transitions