共查询到19条相似文献,搜索用时 187 毫秒
1.
2.
研究了外腔钨酸铅(PbWO4)拉曼激光器的输出特性,介绍了由1064nm纳秒脉冲激发的PbWO4固态拉曼放大器。实验所用的抽运源是电光调Q的Nd…YAG纳秒激光器。对于外腔PbWO4拉曼激光器,当入射抽运脉冲能量为40mJ时,实验测得一阶斯托克斯脉冲的最大转换效率为13%,当入射抽运脉冲能量为48mJ时,实验得到包括一阶斯托克斯脉冲在内的总散射光的转换效率为34%,获得的二阶斯托克斯脉冲的转换效率为23%。PbWO4拉曼放大器是对外腔PbWO4拉曼激光器产生的一阶斯托克斯脉冲进行放大,实验获得的放大后一阶斯托克斯脉冲的最大输出能量为11mJ,放大倍数为3.3。 相似文献
3.
4.
《量子电子学报》2014,(1)
正在斯托克斯位移过程中,当有一阶斯托克斯光子产生后,若入射光子的密度足够高,即可产生二阶甚至高阶斯托克斯光子。若入射光子密度相对较低,不能产生二阶斯托克斯过程,则一阶斯托克斯过程的转换效率也很低。因此,很难实现高效并且纯净的一阶斯托克斯光输出。给出了一种采用偏振耦合输入的拉曼激光谐振腔的实验研究结果。该腔在有效抑制二级斯托克斯光产生的同时,实现了高效的一阶斯托克斯激光输出。采用的斯托克斯谐振腔的泵浦激光源波长532 nm,脉宽10 nm,脉冲重复频率30 kHz、该532 nm激光是由波长为1064 nm的二极管泵浦Q开关激光通过LBO晶体倍频得到。在通过b-cut的KGW(KGD(WO_4)2)晶体后,得到的一阶斯托克斯激光波长为559 nm,二阶斯托克斯激光波长为589 nm。为实现上述高纯度高转换效率的559 nm激光输出,一种逻辑上较为简单的方法是采用HR532 nmAR589 nm,且对559 nm有较高反射率的输出腔镜。但由于三个波长间距较小,要实现这样的腔镜镀膜比较困难,且价格不菲。采用泵浦光偏振耦合输入斯托克斯激光腔的方法,即将线偏振的532 nm激光通过α-BBO晶体走离进入斯托克斯腔内的振荡激光光路、腔内加入一片对532nm和589 nm光为半波片,对559 nm光为全波片的特殊波片、从而实现只有559 nm的一阶斯托克斯光可以在谐振腔内多次振荡,而532 nm的泵浦光和589 nm的二级斯托克斯光则在小于等于一次腔内往返光程时即通过α-BBO晶体走离而离开该谐振腔,造成远大于其腔内增益的损耗。基于以上偏振耦合输入斯托克斯谐振腔设计,实现了6.2 W的纯净559 nn激光输出、入射激光至一阶斯托克斯输出激光的能量转换效率达39%、在输出激光中,泵浦光能量与一阶斯托克斯激光能量之比小于0、7%,二阶及高阶斯托克斯激光与一阶斯托克斯激光能量之比小于0.1%、 相似文献
5.
6.
使用脉冲Nd:YAG四倍频激光抽运充有纯D2气体和D2/He混合气体的拉曼池.实验研究了受激拉曼散射的能量转换效率和能量稳定性与系统主要参量,包括抽运光能量、D2气体压强和加入惰性气体He的关系.实验表明,适量惰性气体He的加入在没有降低一阶斯托克斯散射光(S1,波长:289.04 nm)能量稳定性的前提下,有利于提高其能量转换效率,最大能量转换效率达到22.1%.通过实验分析,得到了受激拉曼散射一阶斯托克斯散射光的能量转化效率和能量稳定性的优化条件. 相似文献
7.
8.
报道了外腔抽运的969nm SrWO4反斯托克斯拉曼激光器的特性。利用主动调Q Nd:YAG激光器产生的1064nm激光作为抽运源,SrWO4拉曼谐振腔的光轴与抽运光的传播方向偏离一个角度,实现了抽运光、一阶斯托克斯光和一阶反斯托克斯光之间的非共线相位匹配,得到了一阶反斯托克斯光和一至三阶斯托克斯光的输出,测量了输出激光的脉冲能量、时间和光谱特性。当抽运光能量为120mJ时获得的969nm反斯托克斯光的最大输出能量为0.74mJ,脉冲宽度为3.9ns。同时,获得的斯托克斯光的总能量为23.9mJ,其中1323nm二阶斯托克斯光的输出能量为19.6mJ。由抽运光向斯托克斯光和反斯托克斯光转换的总效率为20.5%。 相似文献
9.
10.
11.
受激喇曼散射(SRS)高功率激光频率转换的重要途径,特别是在近真空紫外波段、近红外、中红外波段更因其具有简便性和高效率而引人注目。由于固体或多数液体对光的吸收和色散,限制了入射光的强度,从而限制了输出的Stokes线及反Stokes线的强度和级数。此外,某些非线性效应较显著的液、固体分子的复杂性,增宽了输出Stokes及反Stokes线的谱线宽度;许多固体和液体的喇曼频移也比较窄,不适合用于频率转换。因此,要利用受激喇曼效应的频移来获得宽范围新波段上的可调谐激光源,往往利用气体中的SRS效应。高压H_2气是有大的 相似文献
12.
van den Heuvel J.C. van Putten F.J.M. Lerou R.J.L. 《Quantum Electronics, IEEE Journal of》1993,29(8):2267-2272
An astigmatic focus has been used to increase the conversion efficiency of a Raman cell at high pump energy. Experimental and numerical results show that the increased conversion is due to the reduction of cascade second order Stokes. It is shown that other effects, namely Brillouin scattering, anti-Stokes generation, and ground-state depletion, are negligible for the present experimental setup. The experimental and numerical calculations are in agreement. In particular, good agreement was obtained for the cross-over energy, i.e., the pump energy where the ordinary and the astigmatic focus give the same Stokes energy. Below this energy an ordinary focus gives a higher conversion than an astigmatic focus, while above this energy this is reversed 相似文献
13.
A scheme of backward Raman pulse compression is proposed in which the backward first Stokes pulse is amplified under stationary conditions and the backward second Stokes under transient conditions by choosing an appropriate Raman medium. The compression factor and efficiency are improved by insertion of selective absorbers for the second Stokes component. The feasibility of such a scheme is demonstrated by an experiment in which a 249-nm UV pulse of 20-ns duration has been compressed into a 30-ps pulse with an power gain of 150 and energy conversion efficiency of 22%. Higher compression ratio and higher efficiency is expected under improved conditions 相似文献
14.
基于氢气填充空芯光子晶体光纤的全光纤型气体拉曼光源特性 总被引:1,自引:0,他引:1
理论和实验研究了调Q光纤激光脉冲抽运基于氢气填充空芯光子晶体光纤气体腔的全光纤型气体拉曼光源的特性。抽运光脉冲波长为1064.7nm时,产生的Stokes频移光波长为1135.7nm。理论和实验结果均表明,产生的Stokes频移光脉冲宽度远小于抽运光脉冲,并且,Stokes频移光脉冲宽度随抽运光脉冲能量的提升而增加。此外,减小抽运光脉冲宽度,可以降低拉曼阈值抽运能量、提高Stokes频移光的转换效率。在重复频率为5kHz、脉冲宽度为125ns的调Q光纤激光脉冲抽运下,实验测得拉曼阈值抽运能量和拉曼阈值点处转换效率分别为2.13μJ和9.82%。 相似文献
15.
The dependence of the first Stokes stimulated Raman conversion efficiency of fourth-harmonic radiation from a Nd:YAG laser at 266 nm has been studied for the isotopic species H2, HD, and D2 as a function of gas pressure and laser energy using a low numerical aperture (~4.5×10-3) pumping geometry. While the laser energy threshold for first Stokes conversion is seen to vary significantly between the species it has been found that photon conversion efficiencies of at least 50% can be achieved for all of them for laser pump energies at 266 nm ⩽50 mJ/pulse. This study provides a new measurement of the differential cross section for stimulated Raman scattering in HD of 8.1±2.4×10-29 cm2/sr at 266 nm and at high pressures, and agreement is found with previous measurements of the cross sections for H2 and D2. The results have been used to optimize the laser transmitter system for a differential absorption lidar (DIAL) system to measure tropospheric ozone concentration profiles 相似文献
16.
Shuanghong Ding Xingyu Zhang Qingpu Wang Fufang Su Shutao Li Shuzhen Fan Zhaojun Liu Jun Chang Sasa Zhang Shumei Wang Yuru Liu 《Quantum Electronics, IEEE Journal of》2006,42(1):78-84
A highly efficient extracavity Raman laser pumped by the infrared nanosecond laser pulses is presented utilizing the recently recommended Raman medium-strontium tungstate crystal (SrWO/sub 4/). The maximum conversion efficiency of the first and second Stokes pulses both reached about 50%, and the maximum total conversion efficiency of the first and second Stokes was obtained to be 70% in the experiment. The conversion efficiency dependence on the polarization and the temporal characteristics of the Stokes and pump pulses were also studied. A theoretical model for the solid-state extracavity Raman laser was established based on the radiation transfer equations describing stimulated Raman scattering processes, and solved numerically. This model can accurately predict the energy transfer dynamics observed in extracavity Raman lasers. 相似文献
17.
18.
Stimulated Raman scattering (SRS) experiments have been performed using an ∼2 J,sim0.4 mu s pulsewidth XeF* laser as the pump and high-pressure molecular hydrogen as the Raman-active medium. The SRS conversion efficiency and spectral distribution have been characterized as functions of H2 pressure and pump laser focal parameters. Energy conversion efficiencies of >60 percent have been obtained, with the converted energy in first and second Stokes radiation, at 414 nm and 500 nm, respectively. 相似文献
19.
GdVO4晶体的受激拉曼散射 总被引:10,自引:3,他引:7
采用熔体提拉法生长出了高质量的a轴和c轴GdVO4单晶。测量了GdVO4晶体的室温透过光谱,结果表明GdVO4晶体的短波透过截止边为338 nm,长波透过截止边大于3000 nm,透过范围覆盖紫外、可见、近红外和部分中红外波段,因此可以在较宽波长范围内实现拉曼激光频移。研究了GdVO4晶体在532 nm和355 nm皮秒激光脉冲抽运下的受激拉曼散射(SRS)。采用腔外单次通过方式,获得了3级斯托克斯线(557.98 nm,586.86 nm,618.92 nm)和1级反斯托克斯线(508.01 nm),得到GdVO4晶体一级斯托克斯拉曼散射的稳态增益系数为26.6±0.2 cm/GW,二级斯托克斯拉曼散射的稳态增益系数为14.0±0.2 cm/GW,受激拉曼散射的整体转换效率达到43%。报道了GdVO4晶体355 nm激发的受激拉曼散射,观察到2级斯托克斯谱线(365.9 nm,378.1 nm),在此条件下测得一级斯托克斯谱线的拉曼增益高达114±9 cm/GW。 相似文献