飞秒laser脉冲辐照水膜产生的X射线和声的相关发射

Upconverting nanodots of nayf4yb3er3 synthesis characterization and uv visible luminescence study through ti sapphire 140 femtosecond laser pulses

In this work, dot-sized upconversion nanocrystals (UCN-dots) with diameter c.a. 3.4-0.15 nm have been synthesized. These UCN-dots exhibit visible emission (at 497, 527 and 545 nm) under the excitation with 980 nm CW-NIR laser. Further, these UCN-dots exhibit high energy upconversion emission (UV region, 206 to 231 nm) with Ti-Sapphire Femtosecond laser of 140-femtoseconds duration at 80 MHz repetition rate at different excitation, which has never been reported. This is interesting to report that the generation of high energy UV-Vis emission and their shifting from 206 to 231 nm for the UCN-dot…

单飞秒laser脉冲与云母相互作用

Single femtosecond laser pulse interaction with mica

与金属和半导体相比，超快、飞秒激光脉冲与电介质材料的相互作用表明，对于激光材料改性，例如激光烧蚀，电介质材料具有显著更高的激光通量阈值要求。玻璃的实例是晶体材料，例如石英和蓝宝石，以及非晶玻璃。已经发现，在具有可忽略的线性吸收的波长处的飞秒激光脉冲与电介质之间的相互作用很弱，因此通常使用多脉冲照射以观察显著且可量化的效果。在这项研究中，电介质是晶体，层状，天然矿物白云母，云母与分子式KAl_2（Si_3 Al）O_10（OH）_2。白云母，新的分裂，被用于广泛的技术和科学应用，包括作为绝缘材料的电子产品和作为一个超平和超净基板。发现单一的、~800 nm波长、~6微米光斑尺寸、~150 fs激光脉冲导致激光修改拓扑结构的系统范围，作为单一激光脉冲的能量密度的函数，包括材料的块体去除。飞秒激光脉冲/材料的相互作用是大于预期的标准电介质在给定的能量密度。光学表面轮廓和FESEM被用来表征拓扑结构。对比这两种技术的结果支持使用光学表面轮廓来表征材料改性，尽管与FESEM相比，其在横向分辨率上存在局限性。层间矿水含量的天然白云母提出的主要原因，云母行为不同的标准电介质时，用一个单一的800 nm飞秒激光脉冲照射。

Damage threshold evaluation of thin metallic films exposed to femtosecond laser pulses: the role of material thickness

The employment of femtosecond pulsed lasers has received significant attention due to its capability to facilitate fabrication of precise patterns at the micro- and nano- lengths scales. A key issue for efficient material processing is the accurate determination of the damage threshold that is associated with the laser peak fluence at which minimal damage occurs on the surface of the irradiated solid. Despite a wealth of previous reports that focused on the evaluation of the laser conditions that lead to the onset of damage, the investigation of both the optical and thermal response of thin fi…

高重复频率飞秒脉冲辐照下热累积对钢上LIPSS的形貌、碎屑沉积及润湿性的影响

Influence of Heat Accumulation on Morphology Debris Deposition and Wetting of LIPSS on Steel upon High Repetition Rate Femtosecond Pulses Irradiation

研究10 kHz至2 MHz飞秒脉冲下钢表面LSFL的热累积、碎屑再沉积与润湿行为，并结合FTCS一维热模型确定高重复频率加工的最佳条件。

Measurement of ultrashort laser ablation of four metals (Al, Cu, Ni, W) in single pulse regime

We provide measurements of ablation of four post-transition and transition metals (aluminum, copper, nickel and tungsten) irradiated by single 800 nm laser pulses, in ultrashort regime from 100 fs pulse duration down to 15 fs covering a temporal range little explored yet. For each metal and pulse duration tested, we measure its ablation characteristics (depth and diameter) as a function of incident energy allowing us to determine its laser-induced ablation threshold and ablation rate in single-shot regime. For all metals studied, we observe constant ablation threshold fluence as a function of …

薄水流双脉冲激励下THz波辐射的巨增强

Giant enhancement of THz wave emission underdouble pulse excitation of thin water flow

利用太赫兹时域光谱仪和盖革计数器，在薄而平坦的水流透射面和反射面同时测量了双飞秒激光脉冲（800 nm，35 fs，变换限幅，0.5 kHz，延迟时间15 ns）照射下的太赫兹波和硬X射线辐射.太赫兹波发射光谱显示出其动态峰值向低频移动，在两个脉冲之间的延迟时间为4.7 ns时，|E| ^2的最高强度增强超过1.5 x 10^3倍，而在相同的实验条件下，X射线强度增强仅限于0 ns时的20倍左右。从激光烧蚀水流的角度讨论了预脉冲照射引起太赫兹波发射光谱变化和强度增强的机制。

Laser-induced electron dynamics and surface modification in ruthenium thin films

We performed the experimental and theoretical study of the heating and damaging of ruthenium thin films induced by femtosecond laser irradiation. Results of an optical pump-probe thermoreflectance experiment with rotating sample allowing to significantly reduce heat accumulation in irradiated spot are presented. We show the evolution of surface morphology from growth of a heat-induced oxide layer at low and intermediate laser fluences to cracking and grooving at high fluences. Theoretical analysis of pump-probe signal allows us to relate behavior of hot electrons in ruthenium to the Fermi smea…

切片中的光：如何实现精确的激光加工？

Light in Slices: How to Enable Precise Laser Processing?

本文探讨了如何利用飞秒激光脉冲实现高精度材料加工，分析了其高峰值强度和短持续时间带来的优势，并探讨了材料加工中的限制因素及解决方案。

通过掠入射XFEL散射和衍射探测激光驱动的表面和亚表面动力学

Probing laser-driven surface and subsurface dynamics via grazing-incidence XFEL scattering and diffraction

开发了一种掠入射X射线平台，结合GISAXS和GID，以皮秒分辨率同时探测飞秒激光照射金膜的表面纳米形貌和亚表面晶格动力学，克服了同步辐射通量限制，为超快激光-物质相互作用和温稠密物质理论提供严格基准。