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1.
马洪良 《原子与分子物理学报》2002,19(2):153-155
原子光谱中,同位素移位和超精细结构光谱是少数几个能够将原子物理和原子核物理这两个不同的物理分支联系起来的课题之一.利用共线快离子束-激光光谱学方法测量了单电荷态钕离子4f45d6G3/2→(26041)°5/2跃迁(波长577.21 nm)的共振光谱,得到了所有7个稳定同位素(A=142~146,148,150)之间的能量移位和2个奇同位素(A=143,145)的超精细结构光谱. 相似文献
2.
用实验和数值模拟两种方法研究了高非线性光子晶体光纤中飞秒激光脉冲的传输特性和超连续谱的产生机理,给出了抽运脉冲在三种不同中心波长情况下输出光谱展宽并形成超连续谱的实际测量及理论模拟结果.研究表明:在零色散波长抽运时,光谱展宽以自相位调制为主,同时三阶色散的影响明显,传输脉冲在时域内出现振荡次峰.而在反常色散区抽运时,光谱展宽的初期以自相位调制为主,随后根据抽运功率的不同孤子自频移、高阶光孤子的裂变和四波混频效应会逐渐增强,进而成为光谱展宽的主要原因.与此相应,在时域中能明显看到孤子的形成和红移,飞秒传输脉
关键词:
光子晶体光纤
高非线性光子晶体光纤
飞秒脉冲激光
超连续谱 相似文献
3.
在100TW掺钛蓝宝石飞秒激光器上利用光学CCD相机和光学多道分析仪,分别在靶背法线方向测量了超热电子光辐射的空间分布和光谱.测量结果显示:光辐射空间分布图案呈圆环状,而辐射区域有发散角和光强分布,且包含多种辐射成分.光辐射光谱在800nm附近出现尖峰,是激光的基频(ω0)波,这一现象归因于超热电子束在输运的过程中产生的微束团而引起的相干渡越辐射(CTR).随着激光能量的增加,CTR光谱峰向红光方向移动,基频波红移的主要原因是由于等离子体临界面的迅速膨胀.如果考虑超热电
关键词:
超热电子
光辐射
共振吸收
红移 相似文献
4.
皮秒级时间分辨超快高能脉冲激光光谱 总被引:1,自引:0,他引:1
介绍了一种利用光电摄谱法和条纹管相结合测量ps级时间分辨超快高能脉冲激光光谱的方法。论述了条纹相机工作原理和平面衍射光栅的分光原理,分析指出利用介绍的装置,可以实现波长300 nm ~1 600 nm、脉宽>2 ps超快高能脉冲激光的光谱测量。采用1 054 nm超快高能脉冲激光器,实验得到了条纹像,对条纹像进行数据处理后得到测量光谱曲线,通过能量标定后,得到了超快高能脉冲激光器实际光谱曲线,验证了ps级时间分辨超快高能脉冲激光光谱方法。讨论了系统中耦合透镜组对光谱测量和光纤色散角对条纹图像的影响,论述了ps级时间分辨超快高能脉冲激光光谱的作用。随着条纹管制造技术的飞速发展,该方法可用于fs级激光光谱的测量。 相似文献
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利用亚纳焦量级、脉冲宽度为100 fs的激光脉冲在双折射光子晶体光纤中获得了450—1050 nm 的超连续光谱,且超连续光谱具有明显的分立峰状结构.分析了光谱中分立峰状结构产生的物理机制,抽运光波长处于接近零色散波长的反常色散区,形成高阶光孤子,由于高阶非线性和高阶色散的影响,高阶孤子分裂成多个基孤子,使初始光谱上演化出红移的光孤子成分和蓝移的色散波成分.理论模拟了飞秒激光脉冲在光纤中的色散特性和传输特性,较好地解释了实验结果.
关键词:
光子晶体光纤
超连续光谱产生
孤子分裂
脉冲俘获 相似文献
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超快激光经过透明介质时由于非线性作用光谱会得到展宽,甚至能够产生超过一个倍频程的相干超连续光谱,这样的光源能够压缩得到几个甚至单个光周期的超短脉冲,并在现代超快科学的各个领域得到了广泛应用.实验中已经在气体、液体和固体中都观测到了光谱的展宽,目前较为成熟的方法是使用充满惰性气体的空芯光纤和具有高非线性效应的固体材料展宽光谱.但空芯光纤由于芯径限制无法用于高能量激光脉冲的光谱展宽,而固体材料又容易被高功率密度的脉冲激光损坏.随着激光技术的发展其脉冲能量不断提高,一种新的、利用多片薄固体介质实现光谱展宽的方式被提出.多片薄的非线性介质可以实现光谱展宽的逐片累积,而且避免了激光在介质中因自聚焦产生过高功率密度带来的损坏.目前使用这种方法已经在实验上得到了近毫焦尔量级的倍频程光谱,覆盖了近紫外到中红外的整个区域,并实现了脉冲压缩.本文简要回顾了超快激光在固体中光谱展宽的发展历程,概述了新型薄片固态介质产生超连续光谱的原理,对近年来使用此新方法的实验进行了简要分析,并对其发展前景进行了展望. 相似文献
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当共线传输的双色强激光脉冲满足时间重叠时,其等离子体通道间将出现强烈的耦合作用,由此引起的交叉相位调制可产生强烈的非线性效应,使紫外超短脉冲的频谱展宽效应得到增强.将由钛宝石激光系统经三倍频得到的能量为045 mJ、带宽为15 nm的紫外脉冲和能量为71 mJ的近红外脉冲共线聚焦后,在氩气样品池中分别诱导产生等离子体通道,发现紫外脉冲光谱受到明显调制.调制后的光谱半高全宽增至64 nm,为聚焦前谱宽的4倍,是单束紫外脉冲成丝时谱宽的25倍.实验着重研究在不同时间延迟、耦合位置和气体压强情况下,双
关键词:
紫外超快脉冲
双色光丝
非线性效应
光谱展宽 相似文献
10.
实现了一种适合于相干拉曼光谱探测的宽带超连续谱光源的方法,使用1 064nm飞秒激光泵浦全正色散光子晶体光纤,并用光栅对对脉冲进行压缩,最终获得了脉宽178fs,频谱范围处于760~1 300nm的超连续谱光源.对超连续谱脉冲的时间频谱结构进行了分析,未经过压缩的超连续谱的脉冲宽度达到1.43ps,不同频率的成分之间延迟较大,但基本上呈线性平滑分布,因此可以使用光栅对进行色散补偿;此外,提高泵浦光的功率虽然能够增加光谱展宽,但会引入高阶色散,并不利于色散补偿.最后,使用该超连续谱搭建的三色相干反斯托克斯拉曼散射光谱探测系统,测量了苯甲腈溶液的相干反斯托克斯拉曼散射信号光谱,同时获得了3 200cm~(-1)范围内的所有振动模式,验证了该超连续光谱的性能. 相似文献
11.
对ZnCl2溶液在不同外界环境光存在下的激光拉曼光谱的影响进行了探讨.研究表明不同的外界环境光,自然光和室内荧光灯光,都会对拉曼光谱产生干扰效应,存在着特征谱线,倒峰或尖锐正峰.虽干扰表现不同,但都有影响,不能忽略.因此,在进行溶液拉曼光谱检测时,需在暗室或暗罩中进行,以完全隔离外界环境光的影响. 相似文献
12.
Single-crystal K(2)ZnCl(4) doped with Co2+ has been grown successfully by use of the Czochralski technique. The absorption spectrum of the crystal was measured. The most intense line, centered at 650 nm, was associated with the transition (4)A(2)-->(4)T(1P), and a novel and important result that corporate transition (co-transition) between (4)A(2)-->(4)T(1F) and (4)A(2)-->(4)T(2) of Co2+ in the region of 1300-2400 nm was found and discussed. The mechanism that caused the phenomenon was explained by energy-level splitting theory. In the tetrahedral approximation, using the quantum and Tanaba-Sugano theories, Racah parameter B and crystal field parameter 10Dq were calculated. The optical energy gap, deduced to be 4.82 eV, was lower than that of pure K2ZnCl4. 相似文献
13.
计算机技术的迅速发展使分子动力学模拟成为可能。这是一种直接方法用以更详细地了解液态的结构。文章介绍在分子动力学模拟产生的一系列平衡瞬态构型基础上的等近邻键序参数方法和使用这一方法对若干熔体局部结构的研究,包括若干碱金属卤化物熔盐,CaF2快离子态和熔融态,熔融态ZnCl2和Rb2ZnCl4,BBO熔体和晶体生长母液等。 相似文献
14.
To investigate the effect of preferential solvation the ultrasonic attenuation (2-50 MHz) and velocities (3 MHz) of ZnCl(2) and 2-chloroacetamide (ClCH(2)CONH(2)) in water and its quasi-binary mixtures with the ratio (ZnCl(2)+ClCH(2)CONH(2)):H(2)O=1:55 at 298.15 K have been measured. The creation of specific complexes in the ClCH(2)CONH(2)-H(2)O-ZnCl(2) system have a relaxational character which, within the measurements of ultrasonic absorption in the frequency range 2-50 MHz, have been observed. On the base of these properties the kinetic and dynamic parameters of the observed relaxation have been calculated. To bring into relief the influence of Cl atom in the 2-chloroacetamide molecules for complexation process it has been investigated also the system AA-H(2)O-ZnCl(2). The next step of searching was to investigate the system of CHAA-H(2)O-ZnBr(2), to reduce the influence of Cl atom within ZnCl(2) molecule at the complexation process. The main aim of presented study was to investigate the possibility of complexation in the aqueous solutions of ZnCl(2) with the part of 2-ClCH(2)CONH(2) (CHAA). With regard of big complexing ability of zinc, there exist a theoretical possibility of attachment CHAA to the inner coordination sphere of zinc through chloride atom. There can create here outer-sphere as well as inner-sphere complexes. As a results the observed relaxation processes have been attributed to creation and disintegration the following complexes: Zn(H(2)O)(2)(CHAA)(4)(2+) and Zn(2+)(H(2)O)(3)(CHAA)Cl(2)(-). 相似文献
15.
The structural luminescence spectra of protoporphyrin IX solid solutions in ethanol and hydrochloric acid were obtained under selective laser excitation in the region of the inhomogeneouly broadened pure electronic and vibronic bands at T = 3.8 K. The dependence of the excitation selectivity on the excitation frequency was investigated. The vibrational frequencies of protoporphyrin IX were obtained in the ground and excited electronic states when the excitation frequency has been scanned in the region of pure electronic and vibronic bands, respectively. A universal apparatus is described for the investigation of the absorption and luminescence spectra of polyatomic molecules in the temperature range from 3.5 to 300 K under the dye laser excitation tunable in the spectral region 265–365 nm, 435–730 nm, detection of spectra in the region 300–900 nm with a polychromator and silicon intensified image detector and processing of the spectral information with an optical spectrum analyser controlled with a microcomputer. 相似文献
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Fernandez J Iparraguirre I Aramburu I Illarramendi A Azkargorta J Voda M Balda R 《Optics letters》2003,28(15):1341-1343
We report for the first time to our knowledge an experimental demonstration of wavelength self-tuning in a K5Nd(MoO4)4 broadband-emitting laser crystal (KNM), as well as a theoretical treatment of the system based on its birefringence properties. The self-frequency-tuning of the laser along the full spectral range of the KNM crystal was obtained by rotating a birefringent gain plate in its own plane. The gain plate was placed inside a resonator at Brewster's angle. The tuning characteristics of the spectral filter were obtained by use of the Jones vector formalism. The calculated wavelength-selective tuning precisely matches the experimental observations. 相似文献
18.
A substantial spectral shift of the UV-laser induced luminescence in the Ag nanoparticles (NP) doped by Er3+ ions attached to ITO substrates was observed at T = 4.2 K. We have established high energy spectral shift of principal luminescent maxima (from wavelength equal to about 1.45 up to 1.15 μm) with increasing of the pumping nanosecond nitrogen laser power density up to 1.1 GW/cm2 operating at λ = 337 nm. With increasing Erbium content with respect to Ag the spectral shift and spectral line broadening increase. It may be caused by specific features of trapping level occupation kinetics on interfaces NP/ITO substrate. The observed process is fully reversible. The luminescence is observed only during excitation by the 337 nm laser pulses and is absent for laser pulses operating at other wavelengths (like excimer laser at 218 nm and nitrogen laser at 371 nm). 相似文献
19.
3 ) stimulated photorefractive backscattering (SPBS) phase conjugator. The SPBS process was successfully achieved by the combination
of the short-wavelength diode laser and the highly doped photorefractive BaTiO3:Co crystal. The spectral width of the diode laser is reduced to 7.2 pm because of the narrow spectral bandwidth of the gratings
[with wave number of K=2k(2k gratings)] formed in the SPBS phase conjugator, compared with the transmission grating formed
in the conventional cat conjugator, which was used previously. The SPBS phase conjugator was successfully used to suppress
self-frequency scanning, and wavelength-stable oscillation of the SPBS phase-conjugator-coupled diode laser was achieved.
Received: 4 November 1996/Revised version: 12 February 1997 相似文献
20.
Luminescent properties of PbI2 and PbI2: 0.5 mol % MnCl2 crystals under X-ray or N2-laser excitation are studied experimentally. The measurements are performed at temperatures ranging from 85 to 295 K. For PbI2 crystals under laser excitation, spectral bands with peaks near 495 and 512 nm, respectively, are observed at 85 K. With X-ray excitation at the same temperature, luminescence is observed in the 515-and 715-nm bands. The doping decreases the intensity in the 515-nm band, increases it for longer wavelengths, and shifts the highest peak to 700 nm. At 85 K, the doping has an insignificant effect on the excitation energy accumulated by trapped electrons. Certain PbI2 crystals also exhibit a peak in a region of 580–595 nm. This peak becomes much higher if the crystal is treated with an N2 laser at room temperature or if it is heated to 450–485 K. As the measurement temperature rises from 85 to 295 K, luminescence intensity decreases considerably. With X-ray excitation at room temperature, the yield of PbI2: Mn luminescence peaked at 660 nm for doped crystals is about three times larger than the yield peaked at 555 nm for nondoped crystals. The spectral curves and underlying radiative processes are discussed. 相似文献