~(13)CO_2同位素激光器——激光雷达新光源

本文描述了~(13)CO_2同位素激光器的特性和它在激光雷达、激光驾束制导中的应用。报道了研制的稳频~(13)CO_2同位素激光器,输出单模、偏振,总共25条激光谱线,最大输出功率大于3W。     

CH_3F与~(12)CO_2和~(13)CO_2分子之间的振动能量转移

我们采用Q开关的CO_2激光9.6μmP(20)支泵浦CH_3F分子的v_3振动模,以此作为能源来激发~(12)CO_2和~(13)CO_2分子的弯曲振动模v_2,研究其在非弹性碰撞过程中分子能量转移过程。我们用一种比红外荧光法(LIF)分辩率高一万倍的新方法——二极管激光探测法来得到~(12)CO_2、~(13)CO_2能级粒子数的演变过程。实验测得在1CO_2:1CH_3F气体比例下,从CH_3F的v_8振动模至CO_2的v_2振动模的V-V转移速率为3.3ms~(-1)Tcrr~(-1)。     

3657～3708cm~(-1)范围内CO_2高分辨振转光谱

用可调谐红外二极管激光光谱仪观测了3657～3708cm~(-1)范围内自然丰度的CO_2样品的高分辨光谱。观测到属于不同同位素分子的九个振转谱带中的420条谱线。其中(12)~C(16)~O(17)~O的10011-00001和(12)~C~(16)~O(18)~O的11111—01101这二谱带的V_o值分别比近年美国AFGL Rothman及Bene-diet等人编的CO_2光谱常数表(见 Appl.Opt.Vol.17,2605,1978)所列值小0.287cm~(-1)和大0.048cm~(-1)。确认这二谱带是我们首次观测到的,并扩充了其余7个谱带中观测到的振转线的数目。     

封离型CO_2激光器

CO_2激光器是气体激光器中功率较大、效率较高的一种器件.激光波长在10.6微米附近(相应于CO_200°1—10°0跃迁).自从1964年国际上出现这类器件以来,已有多种的型式.连续波功率从几百毫瓦至几十千瓦,脉冲能量从几毫焦耳到几千焦耳,可以满足各种不同的应用要求.     

序列谱线选支CO_2激光器

通常,普通的光栅选支CO_2激光器在(00°1～[10°0,02°0]_(Ⅰ,Ⅱ)带上可获得调谐范围为9～11微米的几十条激光谱线。然而,在CO_2的放电中,在(00°2-[10°1,02°1]_(Ⅰ,Ⅱ)对能级之间还可以实现粒子数反转,这个被称为“序列”带的新的激光谱带与普通选支CO_2激光器输出的“惯常”带具有相类似的增益分布,在9～11微米波长范围内二者谱线数目大致相同,两两对应相互交错,但又十分靠近。但是,在一个普通的选支激光腔内,由于“惯常”带的增益比“序列”带的增益大很多,受竞争效应的影响,一般看不到“序列”带激光谱线。要获得属于“序列”带的     

CO_2激光束的高频电光调制

一概述由于CO_2激光的频率较微波高10~3～10~4倍,它的信息容量也就比微波高10~3～10~4倍,因此,CO_2激光器是完成大容量激光通讯较好的发射器件。要实现大容量激光通讯,必须有一个宽带调制器将各种信息调制到CO_2激光束上。对于其它应用方面的红外整机,也希望能传送尽可能多的信息。这些都要求发展激光的高频调制技术,以前那种低频调制技术(如调制盘)在这些应用中显然是不能胜任的。     

NH_3斯塔克效应调制同位素~(13)CO_2激光器的半经典理论和实验研究

本文从理论(激光半经典理论)和实验上研究了NH_3分子asQ (6,6)跃迁与同位素~(13)CO_2激光器R(18)支线的相互作用.利用密度矩阵近似,在随时间变化的斯塔克场作用下,在吸收线附近建立起用量子力学描述的多普勒线型吸收系数表示式和理论上     

双波长可调谐TEA CO_2激光器

研制成一种新型双波长可调谐TEA CO_2激光器。该器件结构简单,能同步输出波长不同的两种激光振荡,每一波长均在9.16～10.86微米波段内(约80条谱线)独立可调,双波长脉冲的相对强度和延迟时间均可控制且再现性良好,已在双频法激光分离同位素中得到成功应用。     

CO_2激光器吸引军方

近期CO_2激光技术(包括美国国防部高级研究规划局/美国空军基地的BB/OB工程所用的激光雷达)在战术方面的几项应用引起了军方的注意。10.6微米波长的CO_2激光器与目前用于测距和目标指示的1.06微米Nd:YAG激光器相比,有很大的优越性,如CO_2可以穿透几乎全部战场烟雾,还可同8～12微米波段的红外前视装置(FLIR)兼容。第一代CO_2激光器的确是又大又笨,而且平均效率只在5％左右。由于早期的这些局限性,低功率CO_2激光     

连续波调频C~(18)O~2激光器

一、引言近年来,激光化学、激光分离同位素、激光光泵、激光光谱学和激光测污等领域有了很大的发展,迫切要求激光器扩展调频范围并提高单谱线的输出功率.CO_2有多种同位素丰富的谱线,有希望制成宽范围凋频CO_2激光器.     

Far-infrared laser oscillations from H2CO

Lasting laser oscillation was obtained from H2CO vapor with a longitudinal-flow tube. Ten lasing lines, including six new lines, have been observed in the pressure range of 0.18-0.35 torr. The optimum conditions were 2.5-7.1 kV and 2.5 Hz for excitation voltage and pulse repetition rate, respectively. The pulse shape of the lines was observed by an Ni-W diode.     

Studies of CW lasing action in CO2-CO,N2O-CO, CO2-H2O, and N2O-H2O mixtures pumped by blackbody radiation

A proof of principle experiment to evaluate the efficacy of CO and H₂O in increasing the power output for N₂O and CO ₂ lasing mixtures has been conducted and theoretically analyzed for a blackbody radiation-pumped laser. The results for N₂ O-CO, CO₂-CO, N₂O-H₂O and CO₂-H₂O mixtures are presented. Additions of CO to the N₂O lasant increased power up to 28% for N₂O laser mixtures, whereas additions of CO to the CO₂ lasant, and the addition of H₂O to both the CO₂ and N₂O lasants, resulted in decreased output power     

New far infrared CW optically pumped cis-C2H2F2laser

Lasing on 6 FIR lines is reported for the new laser molecule cis-C2H2F2with high conversion efficiencies up to 7 percent of the maximum theoretical limit. A set of molecular selection criteria was used to predict efficient FIR lasing from this molecule, and analysis of the laser performance has increased the basic understanding of the molecular parameter contribution to high conversion efficiency. From this work a refined set of selection criteria has evolved that may be used to predict additional efficient laser molecules.     

New CW far-infrared lasing in14NH3using Stark tuning

New CW far-infrared lasing lines have been obtained in¹⁴NH3using either CO2or N2O pump lasers. Except for two of them, all of the lines have been obtained using the Stark effect to tune the infrared laser line and the infrared ammonia transition into frequency coincidence. Electric fields up to 18 kV/cm have been used with pressures of 20 millitorr.     

序列谱带选支CO_2激光器

本文介绍一种能产生CO_2(00~02—[10~01,02~01]_(Ⅰ,Ⅱ)带激光跃迁,从而使普通封闭选支CO_2激光器输出谱线数目加倍的腔内热吸收池技术及其实验结果。     

Thermal shifts of the spectral lines in the 4F3/2 to 4I11/2 manifold of anNd:YAG Laser

A report is presented of the thermal shifts of eleven of the twelve lines from the ⁴F_3/2 Stark energy levels to the ⁴I_11/2 energy levels in an Nd:YAG laser for a temperature change from 20-200°C. The thermal shift difference between the Stark sublevels R₁, R₂ in ⁴F_3/2 is found to be about -0.6±0.6 cm^-1/100°C. Within experimental uncertainty, all of the lasing lines either moved to longer wavelength or remained unchanged with increasing temperature     

12 µm Raman lasers in NH3pumped by low-power CO2laser pulses

We report the operation of optically pumped 12 μm lasers in NH3using peak pumping powers as low as 2 W. These low pumping powers represent a 1-2 order-of-magnitude improvement over previously published threshold values. Measurements of the lasing offset frequency clearly demonstrate that a two-photon Raman process is responsible for optical gain at 12 μm. In light of our results, we discuss the feasibility of an optically pumped CW 12 μm laser.     

CO(v = 2:1) laser transitions from He-air-CH4

A flowing electrochemically excited liquid-nitrogen-cooled He-air-CH4-(CO) laser was operated inQ-switched fashion yielding 20 CO laser lines below 5.0 μ. These laser lines were measured to occur from 4.7848 to 4.9880 μ. The lines were all identified to result fromP(J)_{upsilon,upsilon'}CO vibrational-rotational transitions as low asupsilon = 2:1. Nine suchupsilon = 2:1transitions were measured.     

声光调Q CO2激光器波长调谐理论分析与实验研究

采用旋转光栅法实现了声光调Q CO2激光器可调谐脉冲激光输出。理论分析了CO2激光波长调谐特性,发现调节各支谱线腔内损耗是实现激光波长调谐的有效方法。进而理论计算了特定设计波长闪耀光栅的衍射效率与激光波长间的关系,结果显示光栅调谐的激光谱线自准直角与光栅闪耀角一致时具有最高的衍射效率。采用闪耀角分别为31.97（闪耀波长10.59 m）和28.71（闪耀波长9.60 m）的光栅实验研究了声光调Q CO2激光器波长调谐特性,分别获得了65条和75条激光谱线。实验结果显示:光栅设计闪耀波长处于弱激光增益分支时可获得更多条激光谱线,该实验与理论计算结果相符。在脉冲重复频率为1 kHz时,获得10.59 m激光脉冲宽度为160 ns,平均功率4.2 W,脉冲峰值功率26.25 kW,且稳定性良好。     

Near single-line operation of a free-burning CS2/O2/N2O flame laser with a nondispersive optical cavity

The CS2/O2/N2O flame laser has been operated for the first time under conditions in which the spectral output is nearly single line. This transition is theP_{10-9}(17) of CO at 5.4265 μm, the same transition which was observed to oscillate in single-line fashion by Hirose et al. in an electrically initiated CO chemical laser. It is suggested that the unique behavior of this line may be due to its close proximity to aPbranch transition in an adjacent band, namely theP_{9-8}(23) line, such that the gain profiles of the two lines overlap. Calculations suggest that at the conditions of these experiments, the separation of the line centers for this pair is about 0.3 Å or less. TheP_{10-9}(17) transition was also found to be totally absent under certain conditions of high multiline power, particulary at low O2and N2O flows. This may be due to absorption by a high-bandRbranch transition at 5.4266 μm, namely theR_{15-16}(32) line.