共查询到20条相似文献,搜索用时 46 毫秒
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针对激光对红外成像系统的干扰效果是光电对抗领域的一个研究热点,采用波长10.6 μm的CO2调谐脉冲激光器,通过漫反射板反射激光能量到像元数为320×240的多晶硅非制冷焦平面红外热像仪上进行激光干扰红外成像系统的实验。在实验中研究了干扰激光能量、重复频率、波长、光斑大小等激光参数对干扰效果的影响,并从图像质量的角度分析了激光参数对干扰效果的影响。结果表明,随着干扰激光能量密度、重复频率、波长和光斑的增大,干扰效果提高。此外,漫反射干扰的效果证明这种干扰方式是可行的,该方式可避免干扰源成为未来将出现的反辐射光电制导武器的诱饵,为CO2激光干扰装备提供一种新的战术配置方法。 相似文献
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Yuji Utsunomiya Takashi Kajiwara Takashi Nishiyama Kunihito Nagayama Shiro Kubota 《Applied Physics A: Materials Science & Processing》2010,99(3):641-649
We studied a new pulse laser ablation phenomenon on a liquid surface layer, which is caused by the difference between the
refractive indices of the two materials involved. The present study was motivated by our previous study, which showed that
laser ablation can occur at the interface between a transparent material and a gas or liquid medium when the laser pulse is
focused through the transparent material. In this case, the ablation threshold fluence is reduced remarkably. In the present
study, experiments were conducted in water and air in order to confirm this phenomenon for a combination of two fluid media
with different refractive indices. This phenomenon was observed in detail by pulse laser shadowgraphy. A high-resolution film
was used to record the phenomenon with a Nd:YAG pulse laser with 10-ns duration as a light source. The laser ablation phenomenon
on the liquid surface layer caused by a focused Nd:YAG laser pulse with 1064-nm wavelength was found to be followed by the
splashing of the liquid surface, inducing a liquid jet with many ligaments. The liquid jet extension velocity was around 1000
m/s in a typical case. The liquid jet decelerated drastically due to rapid atomization at the tips of the ligaments. The liquid
jet phenomenon was found to depend on the pulse laser parameters such as the laser fluence on the liquid surface, laser energy,
and laser beam pattern. The threshold laser fluence for the generation of a liquid jet was 20 J/cm2. By increasing the incident laser energy with a fixed laser fluence, the laser focused area increased, which eventually led
to an increase in the size of the plasma column. The larger the laser energy, the larger the jet size and the longer the temporal
behavior. The laser beam pattern was found to have significant effects on the liquid jet’s velocity, shape, and history. 相似文献
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F. Chen L. X. Yu X. L. Liu B. Q. Yao G. Li C. H. Zhang Y. Z. Wang Y. L. Ju 《Laser Physics》2012,22(1):91-94
In this paper, we present experimental results concerning on the laser characteristics of Tm:YAG laser and Tm: GdVO4 laser. At room temperature, the maximum output power of Tm:YAG laser and Tm:GdVO4 laser is 210 and 145 mW, respectively. High efficiency can be achieved for both lasers at room temperature. Nevertheless,
compared with Tm:GdVO4 laser, Tm:YAG laser can operate on single frequency with high power easily. As much as 60 mW of 2013.9 nm single-longitudinal-mode
(SLM) laser was achieved for Tm:YAG laser. For Tm:GdVO4 laser 51 mW of 1919.7 nm SLM laser was achieved. The SLM Tm:YAG laser is better for using as a seed laser for coherent wind
measurements and differential absorption LIDAR systems. 相似文献
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基于激光受激辐射损耗原理的远场光学超分辨成像技术,当圆形入射高斯激光经过涡旋相位板调制后,将转变为中心光强为零的圆环形光束,该形状的激光束与光敏聚合物作用,能够制备出具有一定功能的纳米结构。介绍了自主搭建的基于圆环连续激光光源的激光直写系统,以及利用该系统研制的复合纳米结构。当光源为532 nm连续激光输出时,与正性光刻胶作用,得到直径 < 50 nm的纳米柱复合结构,以及整齐均匀的纳米柱阵列结构;与负性光刻胶作用,得到直径 < 100 nm的纳米通道,以及整齐均匀的中央有纳米通道的微米柱复合结构阵列。当光源为405 nm连续光纤激光时,与正性光刻胶作用,也得到了直径小至153 nm的纳米柱复合结构及其阵列。这些纳米结构的基本单元尺寸都突破了光学“阿贝衍射极限”的限制,具有实用潜力。 相似文献
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An environmentally stable mode-locked fiber laser based on nonlinear polarization rotation is experimentally demonstrated. The laser is based on a novel laser configuration that has negligible low-power steady-state reflectivity from one side and, consequently, no CW gain. The laser is self starting and the configuration is implementable as an all-fiber laser with standard polarization-maintaining fiber-pigtailed components. A pulse duration of 5.6 ps is obtained at a repetition rate of 5.96 MHz and at an average power of 8 mW. As an application of the proposed laser configuration, 213 mW of supercontinuum (600-1750 nm) was demonstrated from a fiber laser system with no sections of free-space optics. 相似文献
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Operation and output pulse characteristics of an extremely compact capillary-discharge tabletop soft-x-ray laser 总被引:3,自引:0,他引:3
We report on the operating parameters and laser output pulse characteristics of an extremely compact discharge-pumped 46.9-nm laser of a size comparable with that of many widely utilized visible and ultraviolet gas lasers. This capillary-discharge laser generated subnanosecond laser pulses with energies of as much as 25microJ by single-pass amplification in an 18.6-cm-long argon-plasma column. Measurements of the laser output energy, pulse width, far-field beam profile, and beam divergence are reported. 相似文献
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《Infrared physics》1989,29(2-4):415-422
An illustration of an interaction of pulsed multimode TEA CO2 laser radiation, through or without a mask, as well as of a laser scanning process of a frequency Q-modulated cw CO2 laser beam on glass surfaces has been shown. As an object of investigation glass articles with composition as a standard industrial potassium-boron silicate glass, we have used. A complex of investigations shows that the laser treatment leads to qualitative constant changes (well defined peeling structure) depending on the time surface treatment, defocusing and the pulse length of the laser output. 相似文献
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R. Stoian J. P. Colombier C. Mauclair G Cheng M. K. Bhuyan P. K. Velpula P. Srisungsitthisunti 《Applied Physics A: Materials Science & Processing》2014,114(1):119-127
The spatio-temporal design of ultrafast laser excitation can have a determinant influence on the physical and engineering aspects of laser–matter interactions, with the potential of upgrading laser processing effects. Energy relaxation channels can be synergetically stimulated as the energy delivery rate is synchronized with the material response on ps timescales. Experimental and theoretical loops based on the temporal design of laser irradiation and rapid monitoring of irradiation effects are, therefore, able to predict and determine ideal optimal laser pulse forms for specific ablation objectives. We illustrate this with examples on manipulating the thermodynamic relaxation pathways impacting the ablation products and nanostructuring of bulk and surfaces using longer pulse envelopes. Some of the potential control factors will be pointed out. At the same time the spatial character can dramatically influence the development of laser interaction. We discuss spatial beam engineering examples such as parallel and non-diffractive approaches designed for high-throughput, high-accuracy processing events. 相似文献
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Miroslav Pardy 《International Journal of Theoretical Physics》2006,45(3):647-659
We find the solutions of the Dirac equation for two plane waves (laser beams) and we determine the modified Compton formula for the scattering of two photons on an electron. The practical meaning of the two laser beams is, that two laser beams impinging on a target which is constituted from material in the form a foam, can replace 100–200 laser beams impinging on a normal target and it means that the nuclear fusion with two laser beams is realistic in combination with the thermonuclear reactor such as ITER. 相似文献
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Experiments and Model Calculations on the Emission in the UV-nitrogen Laser Experiments are described which deal with emission in nitrogen lasers. The experimental results have been discussed with known models of emission. The influence of plasma on the radiation has been considered. With the model of amplified spontaneous emission the measured starting point of the beam, and the divergence of the stimulated radiation field could be described. The discrepancy between measured laser pulse energy as a function of laser length and calculation has been interpreted as the influence of decreased group velocity of laser pulse in the non-saturated laser medium. Radiation with small divergence and relatively high power has been generated with a telescope between laser tube and mirror. 相似文献
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混沌光通信与混沌激光测距的研究进展 总被引:1,自引:0,他引:1
激光器的不稳定性是一个普遍现象,而混沌是激光器不稳定性的一个重要特例。近年来,基于混沌激光的一些应用技术相继被提出及完善。结合国内外研究现状,简要介绍了混沌激光在通信及测量领域的应用,包括混沌保密通信、混沌激光雷达和混沌光时域反射仪等技术,并指出了混沌光通信与混沌激光测距的发展趋势。 相似文献
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E. Alemanno A. P. Caricato G. Chiodini M. Martino P. M. Ossi S. Spagnolo R. Perrino 《Applied physics. B, Lasers and optics》2013,113(3):373-378
In this work, we have studied the structure and the morphology of a graphite layer induced on the surface of a polycrystalline thermal grade CVD diamond by focusing a pulsed excimer laser operating at KrF (wavelength 248 nm) and ArF (wavelength 193 nm) mixtures. By micro-Raman and photoluminescence spectroscopies, as well as scanning electron microscopy, we reported the synthesis of a turbostratic t-graphite layer after irradiation with ArF laser. By contrast, irradiating with a KrF laser beam, we obtained a disordered graphite layer with 10 laser shots, while 200 consecutive laser pulses resulted in target ablation. 相似文献
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S. I. Fedotov L. P. Feoktistov M. V. Osipov A. N. Starodub 《Journal of Russian Laser Research》2004,25(1):79-92
The current status of laser thermonuclear fusion research in the leading world scientific centers is characterized by the development of superhigh-power multi-channel laser facilities of megajoule pulse-energy level. The development of such laser installations operating in the pulse-repetition mode with a large number of laser beams, which are necessary for high-symmetry irradiation of a spherical thermonuclear target, is an extremely difficult physical and engineering problem. The concept of a special laser with a controllable function of mutual coherence of radiation is proposed. The studies performed demonstrate that a laser based on such a principle has a number of advantages as compared to the conventional schemes of lasers. In particular, the optical scheme of the laser is significantly simplified, and the cost of the output-energy unit is reduced by several times. The influence of radiation coherence on the homogeneity of the thermonuclear target irradiation is analyzed. The feasibility of suppressing the small-scale self-focusing without application of spatial filtration is shown. A module of the laser facility has been triggered to check the validity of the principles proposed for constructing a laser driver for power stations, and the first experimental results are reported. The possibility of controlling the coherence of laser beams used in ICF experiments without violation of the laser--target system matching is demonstrated, as well as controlling the distribution of the laser radiation intensity in the lens focus. 相似文献
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高集成、高可靠性宽调谐飞秒激光源在超快光谱学、量子光学及生物成像等研究与应用领域具有重要价值.如在生物多光子显微成像中,具有适中能量的宽调谐飞秒激光源不仅可满足多种生物组织荧光激发所需的峰值功率与激发波长,而且也可以显著提升非线性荧光产生效率、成像分辨率以及增大成像穿透深度.采用自主研发的高可靠性全保偏光纤飞秒激光器作为抽运源,基于低色散光纤中高峰值功率飞秒激光脉冲非线性传输引起的光谱加宽机制,本文开展了多波长全光纤飞秒激光产生技术研究.通过采用中心波长在980, 1000,1050, 1070与1100 nm的带通滤波片选择性地对单模光纤输出光谱中最左边与最右边光谱旁瓣进行滤波,在上述中心波长处分别可获得203, 195, 196, 187与194 fs的激光输出.本文提出的基于全光纤飞秒激光脉冲在单模光纤中非线性传输引起的光谱加宽机制与特定光谱选择技术的实验方案为高集成、高可靠性宽调谐飞秒激光源的实现提供了新的研究途径. 相似文献
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用全饱和激光模型对既含有加性又含有倍增噪声的激光场进行理论分析,求出了强度相关时间Tc的数值解和有效本征值λeff的解析解。与实验测量相比较表明,全饱和激光模型与实验吻合得最好,而三次激光模型的偏差较大。 相似文献