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High power supercontinuum generation by dual-color femtosecond laser pulses in fused silica 下载免费PDF全文
High power supercontinuum (SC) is generated by focusing 800 nm and 400 nm femtosecond laser pulses in fused silica with a microlens array. It is found that the spectrum of the SC is getting broader compared with the case of a single laser pulse, and the spectral energy density between the two fundamental laser wavelengths is getting significantly higher by optimizing the phase matching angle of the BBO. It exceeds μJ/nm over 490 nm range which is from 380 nm to 870 nm, overcoming the disadvantage of relative lower power in the ranges far from the fundamental wavelength. 相似文献
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实验研究了平顶飞秒激光经圆锥透镜后在熔融石英中的成丝及超连续辐射.与高斯飞秒激光的成丝对比发现,平顶飞秒激光可以获得在圆锥透镜焦深区域内强度分布更为均匀的等离子体细丝,这一特征更有利于飞秒激光在固体介质中进行微纳加工等领域的应用.并且,在不损伤熔融石英的条件下,平顶飞秒激光成丝可以获得更高能量、更高转换效率的超连续辐射,这是因为若产生光强相近的细丝,平顶飞秒激光所需的初始激光能量更高,此激光能量下产生的细丝长度更长、均匀性更好. 相似文献
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This paper analytically investigates the interaction of light filaments generated by a femtosecond laser beam in air. It obtains the Hamiltonian of a total laser field and interaction force between two filaments with different phase shifts and crossing angles. The property of the interaction force, which leads the attraction or repulsion of filaments, is basically dependent on the phase shift between filaments. The crossing angle between two filaments can only determine the magnitude of the interaction force, but does not change the property of the force. 相似文献
4.
Triggering and guiding of high voltage discharge by using femtosecond laser filaments with different parameters 下载免费PDF全文
This paper demonstrates the triggering and guiding of the stationary high voltage(HV) discharges at 5-40 kV by using plasma filaments generated by femtosecond laser pulses in air.A significant reduction of the breakdown voltage threshold due to the pre-ionization of the air gap by laser filamentation is observed.The discharge experiments are performed by using laser pulses with different energy from 15-60 mJ.The electron density of filaments is detected by sonography method.The influence of the electron density of laser filaments on the triggering and guiding HV discharge is experimentally investigated.The results have shown that the behaviour of plasma filaments can strongly affect the effciency of triggering and guiding HV discharge. 相似文献
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Strong white light emission is observed from femtosecond laser propagation in air. The divergence angle of the white light emission is measured to be about 5mrad. Young's double-slits and a Michelson interferometer are used to investigate the coherence. The wavelength components of the white light emission are identified to have a good spatial coherence and a coherence time of about 0.5ps. 相似文献
7.
Compared with direct ablation, confined ablation provides an effective way
to obtain a large target momentum and a high coupling coefficient. By using
a transparent glass layer to cover the target surface, the coupling
coefficient is enhanced by an order of magnitude. With the increase of the gap
width between the target surface and the cover layer, the coupling
coefficient exponentially decreases. It is found that the coupling
coefficient is also related to the thickness of the cover layer. 相似文献
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Femtosecond Laser-Induced Breakdown Spectroscopy for Detection of Trace Elements in Sophora Leaves 总被引:1,自引:0,他引:1 下载免费PDF全文
Sophora leaves from several areas in Beijing are analysed by femtosecond laser-induced breakdown spectroscopy (femto-LIBS). Although the used spectral detection system is not time-resolved, the spectral lines of trace mineral elements are detected and analysed. It is proven that the femto-LIBS can be an efficient method to detect mineral trace elements contained in tree leaves which is a biomonitor for atmospheric pollution assessment or botanic studies. An interesting case of correlation between trace elements detected in tree leaves and the pollution of the concerned area is presented, for the first time to our knowledge. 相似文献
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