共查询到20条相似文献,搜索用时 31 毫秒
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Schnell M Sävert A Landgraf B Reuter M Nicolai M Jäckel O Peth C Thiele T Jansen O Pukhov A Willi O Kaluza MC Spielmann C 《Physical review letters》2012,108(7):075001
We investigate the properties of a laser-plasma electron accelerator as a bright source of keV x-ray radiation. During the interaction, the electrons undergo betatron oscillations and from the carefully measured x-ray spectrum the oscillation amplitude of the electrons can be deduced which decreases with increasing electron energies. From the oscillation amplitude and the independently measured x-ray source size of (1.8±0.3) μm we are able to estimate the electron bunch diameter to be (1.6±0.3) μm. 相似文献
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报道了一个低阈值宽调谐、被动调Q、单谐振掺MgO的周期性极化铌酸锂晶体(PPMgLN)光学参量振荡器。利用被动调Q的Nd:YVO4激光器作为泵浦源,采用外腔结构,在室温下,实现了PPMgLN晶体的准相位匹配光学参量振荡。光参量振荡的阈值仅为0.27W(单脉冲能量4.5μJ、脉宽35ns);在泵浦光为1.35W(脉冲能量8.2μJ、脉宽35ns),PPMgLN周期为31μm时,获得了161.9mW,3.202μm脉冲激光输出;同时获得了98.5mW的1.594μm信号光输出,总的光光转化效率达到19.3%。通过改变晶体的周期,实现了闲频光3.13~4.19μm,信号光1.43~1.65μm的宽带可调谐激光输出。 相似文献
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Indium phosphorus sulfide, a promising nonlinear optical material, is investigated with respect to elastic constants, anisotropic sound velocity, absorption, refraction and nonlinear optical applications. The elastic tensor components are evaluated from phonon frequency and wavevector data obtained by Brillouin scattering. The ordinary and extraordinary dispersion is determined for the entire transparency range (0.4–8 μm). A 5-parameter Sellmeier equation is fitted to these data and is used to calculate phase matching diagrams for second-harmonic generation and general three-frequency mixing. A possible, attractive application, angle tuned parametric oscillation, is discussed. 相似文献
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I.M. Catalano A. Cingolani C. Calí S. Riva-Sanseverino 《Solid State Communications》1979,30(9):585-588
Experimental evaluation of non-linear susceptibility coefficient d22 for InSe, which is responsible for second harmonic generation in this material at 1.06 and 10.6 μm, is reported and the value compared with GaSe. At the CO2 laser frequency of oscillation, phase matching has been observed and a value of d22 almost equal to d15 for CdSe has been found. The InSe high transparency in the wavelength range 1.1–22 μm, the sizeable value of d22 and the possibility of reaching phase matching condition in the IR range make InSe a potential device for far IR frequency conversion. 相似文献
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建立了一套用于测量生物组织模型偏振后向散射差分光谱的实验系统。在系统中,线偏振光入射到样品表面,检偏器和光谱仪配合记录后向散射光中的平行和垂直分量,随后计算出差分光谱。采用了平均直径分别为5.0μm、9.0μm的两种聚乙烯小球悬浮液进行实验,结果与蒙特卡罗模拟进行对照,验证了实验系统的正确性。初步研究了粒子尺寸分布变化对差分光谱的影响,结果表明,偏振散射差分光谱能敏感地反映粒子尺寸分布的变化,在大小粒子的混合液中,大粒子浓度一定程度的增加,光谱仍保留小粒子的振荡趋势,但差分光强减小。该方法对于早期癌症检测具有潜在应用意义。 相似文献
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《Infrared physics》1989,29(2-4):331-337
In a d.c.-discharge-excited 337 μm HCN laser, amplitude laser noise has been observed at the frequency range of 30 kHz to 1 MHz. The laser noise is classified into three types; oscillation noise having sharp peaks, broadly distributed noise having a center frequency and 1/f-noise. Characteristics of the laser noise have been studied experimentally. The laser noise is caused by small oscillation which appears on d.c.-discharge current and by random fluctuations of current and plasma density. The laser noise has been suppressed more than 30 dB by adjusting the laser parameters such as discharge current, pressure and flow rates of mixed gas (CH44 + N2 + He) and added He. 相似文献
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Analysis is given for a possibility of singly resonant parametric oscillation in the submillimeter range at synchronous pumping
of the ZnGeP2 crystal by a train of 100-ps second-harmonic pulses from the CO2 laser with the radiation energy 1.0 J. The calculation shows that using the ZnGeP2 crystal and the second harmonic of the CO2 laser with the energy density 1.8 J cm−2, one can get the peak submillimeter radiation power from 3.6 to 12 MW in the range from 95 to 300 μm (1.0–3.3 THz). The expected
peak power values are larger than the experimental ones obtained by other nonlinear optics methods. 相似文献
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ZnGeP2 single crystals were grown from Vertical Bridgman method. High-quality near-stoichiometric ZnGeP2 single crystals were obtained in the diameter of 30 mm and length of 120 mm. The results showed that after thermal annealing of the crystals the optical absorption coefficient was below 0.03 cm?1 at 2.05 μm, and ~0.02 cm?1 at 3–8 μm. The low absorption loss ZnGeP2 samples with dimension of 6 × 6 × 18 mm3 were cut from the annealed ingots for 3–5 μm optical parametric oscillation (OPO) experiments. For OPO experiment, we obtained up to 8.7 W output in the 3–5 μm wavelength range (with signal of 3.80 μm and idler of 4.45 μm, respectively) pumped by a 16.3 W 2.05 μm Tm,Ho:GdVO4 laser at pulse repetition rate of 10 kHz, which corresponded to a conversion efficiency of 53.4% and slope efficiency of 64.8%, respectively. 相似文献
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Yu. S. Dadoenkova I. O. Zolotovskii I. S. Panyaev D. G. Sannikov 《Optics and Spectroscopy》2018,124(5):712-719
Difference-frequency generation of terahertz (THz) radiation in a collinear single-crystal scheme with distributed feedback implemented by means of parametric interaction of counterpropagating optical waves in a periodically inhomogeneous medium exhibiting quadratic nonlinearity is investigated. Using ZnTe and CdTe crystals optically pumped at λ = 0.77 and 1.06 μm, respectively, as an example, the possibility of obtaining parametric generation of THz radiation with an optical-to-THz conversion efficiency exceeding 10–3 (with an extremely narrow line of oscillation of less than 4 GHz for ZnTe and less than 9 GHz for CdTe at 1 THz) is demonstrated in the undepleted-pump-intensity approximation. The obtained results can be used for construction of narrow-band lasers in the THz frequency range with an output power (in the quasicw regime of oscillation) of about 105 W/cm2. 相似文献
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A detailed theoretical analysis of the optical properties of periodically poled crystals of lithium niobate for optical parametric
oscillation with excitation at 1 μm is presented. Crystals of congruent lithium niobate with and without MgO-doping are considered.
The choice of materials, their basic optical properties, quasi-phasematching and wavelength tuning ranges, as well as dispersive
effects are discussed. These results provide a useful roadmap for the construction of optical parametric oscillators and generators
operating in the ultrashort pulse regime with excitation at 1 μm. 相似文献
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光镊技术被广泛应用在俘获和操纵微纳米尺寸颗粒, 目前被研究学者普遍接受的俘获吸光性颗粒的机理为光泳力. 本文实现了对空气中被俘获的吸光性颗粒的红外显微观测. 当激光器功率为1.0 W时, 成功观测到被俘获墨粉颗粒(直径约7 μm)和甲苯胺蓝颗粒(直径约为1–20 μm)的温升约为14 K, 为光泳力理论提供了强有力的证据. 另外, 首次用可见光显微镜和红外显微镜同时观测到被俘获颗粒的周期振荡现象, 并分析了振荡现象的产生机理.
关键词:
光镊
光俘获
红外显微 相似文献
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《Optics Communications》1987,63(6):417-420
Laser oscillation in Er-glass, co-doped with Yb sensitiser, has been achieved by pumping with the 1.064 μm output of a Nd:YAG laser. 相似文献
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本文采用折射率面来描述光参量振荡过程的物理图象,获得了光参量振荡过程的相位匹配图象和频率调谐的简单的数学表达式,直观简洁地说明了光参量振荡器频率调谐曲线的调谐行为.我们用1.06μm和0.532μm激光泵浦β-BaB2O4(BBO)晶体,获得了角度调谐的BBO光参量振荡器的调谐范围分别为1.7~2.35μm及0.72~2.1μm,最大能量转换效率为15%,还讨论了输出能量与腔长的关系. 相似文献
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Comparative investigation of long-wave infrared generation based on ZnGeP2 and CdSe optical parametric oscillators 下载免费PDF全文
Long-wave infrared(IR) generation based on type-II(o→e+o) phase matching ZnGeP 2(ZGP) and CdSe optical parametric oscillators(OPOs) pumped by a 2.05 μm Tm,Ho:GdVO 4 laser is reported.The comparisons of the birefringent walk-off effect and the oscillation threshold between ZGP and CdSe OPOs are performed theoretically and experimentally.For the ZGP OPO,up to 419 mW output at 8.04 μm is obtained at the 8 kHz pump pulse repetition frequency(PRF) with a slope efficiency of 7.6%.This ZGP OPO can be continuously tuned from 7.8 to 8.5 μm.For the CdSe OPO,we demonstrate a 64 mW output at 8.9 μm with a single crystal 28 mm in length. 相似文献
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为了验证KTiOAsO4(KTA)晶体用于光参变振荡产生2μm激光的可行性,设计了脉冲式2μm KTA光参变振荡器,采用θ=49°切割的KTA晶体作为光参变振荡晶体,实现了2μm激光的输出;计算了该系统在双谐振情况下的起振阈值,在实验中测得输出的信号光、闲频光波长在2.16μm和2.09μm附近,与理论计算基本吻合,并测量了脉冲宽度。同时选用了对信闲光透过率分别为60%、70%、90%的镜片作为光参变振荡器(OPO)输出镜,测得了三种情况下的输出能量及电光效率的数值;测得了在380 V电压下,输出镜透过率一定时输出能量与光参变振荡器腔长之间的关系曲线,从而验证了KTA晶体用于光参变振荡产生2μm激光的可行性,为下一步的研究工作打下了基础。 相似文献
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基于传输速率方程,对Ho3+:ZBLAN光纤激光器的动态特性——上能级粒子数以 及输出激光功率的弛豫振荡特性进行了数值分析.通过忽略光纤参数对传输方向的依赖性,抽运光 和信号光的功率传输方程被分别简化处理.结果表明,在5I6能级的 粒子数首先经历 一次弛豫振荡后,5I6和5I7能级的粒 子数交替弛豫振荡并达到稳态;同 样,在3μm波长的激光功率首先经历一次弛豫振荡后,3μm和2μm波长的激光功率交替弛豫 振荡并达到稳态,而且,弛豫振荡时的峰值功率远大于稳态时的激光功率.
关键词:
光纤激光器
动态特性
光纤激光理论
钬光纤 相似文献