In this paper, a rare-earth spectral traceability anti-counterfeiting detection technology is proposed. Configure rare-earth samples No.1, No.2 and No.3 with different doping ratios. The spectral signals of these three samples are collected and integrated into a sample library. The traceability anti-counterfeiting detection is to compare the spectral information of the samples to be tested with the established sample library by selecting specific wavelength points for light intensity values. If the sample to be measured meets the light intensity range of the established sample library at a specific wavelength point, the sample model will be output. If it does not meet the light intensity range, the sample to be tested is fake. After testing, the anti-counterfeit rate of samples No.1, No.2 and No.3 can reach 100%. This testing process does not destroy the sample, and the anti-counterfeit effect is unique and reliable.

将梯度气压和梯度温度统一归为梯度密度，从而提出了梯度密度的概念，从理论上讨论了梯度密度对于超强飞秒（fs）脉冲成丝和等离子体通道形成和演化过程的影响。进一步提出了理想密度曲线的概念，并且对于各种不同情况下的理想密度曲线进行了计算和分析。在理想密度曲线下传输的脉冲能在避免多丝的情况下得到最大限度的非线性作用和光谱展宽，从而有望使得压缩后得到的脉冲宽度更短。对理想密度曲线下传输的实质进行了分析和解释，指出在理想密度曲线下传输的实质是保持n2Pc的恒定，在避免自聚焦或者电离的情况下，能使得光脉冲光斑半径在保持一定范围内长距离传输，并且形成一种自波导。

We investigate the angular distribution and average kinetic energy of ions produced during ultrafast laser ablation (ULA) of a copper target in high vacuum. Laser produced plasma (LPP) is induced by irradiating the target with Ti:Sapphire laser pulses of ～50 fs and 800 nm at an angle of incidence of 45o. An ion probe is moved along a circular path around the ablation spot, thereby allowing characterization of the time-of-flight (TOF) of ions at different angles relative to the normal target. The angular distribution of the ion flux is well-described by an adiabatic and isentropic expansion model of a plume produced by solid-target laser ablation (LA). The angular width of the ion flux becomes narrower with increasing laser fluence. Moreover, the ion average kinetic energy is forward-peaked and shows a stronger dependence on the laser pulse fluence than on the ion flux. Such results can be ascribed to space charge effects that occur during the early stages of LPP formation.

通过分段中空光波导对超短脉冲进行光谱展宽，进而压缩获得更窄的飞秒脉冲，是获得周期量级飞秒脉冲的一个简单而有效的方法。对这一方法的最优化问题进行了理论研究和数值模拟。理论计算表明，相等的两段光波导并不是最佳的选择方案，进行优化后的方案在脉冲能量和波形上都会有显著提高。另外，考虑各种物理机制，在两段光波导总长度一定的条件下，适当选取前后两段的长度，可以获得更为理想的脉冲，从而提高脉冲压缩的效率和效果。

We present a numerical study on the evolution of the intense femtosecond pulse propagation in argon by solving the extended nonlinear Schr¨odinger equation which includes the beam diffraction, group velocity dispersion, self focusing, absorption and defocusing due to the electron density, and multiphoton ionization processes. The temporal and spatial profiles and the dynamic picture of the ultrashort pulse propagation in argon under different incident conditions such as initial peak intensity, pressure, beam radius, pulse width, and the focal length are discussed. Because the competition between the self focusing and defocusing effects accompanying with other effects as we mentioned above, we can see the splitting into two or even three peaks of the pulse in the time domain.

Lines are induced on the surface of a photosensitive (FOTURAN) glass by focused femtosecond laser transverse writing with scanning velocity in a wide range of 40-1800 μm/s. The formed lines are analyzed using scanning electron microscope (SEM) and optical microscope (OM). It is observed that three distinct morphologies of lines are produced depending on the scanning velocity. Lines written in low velocity level (40-100 μm/s) and high velocity level (1000-1800 μm/s) are uniform and regular, while those written in moderate velocity level (150-600 μm/s) are rough. The influence of scanning velocity is explained based on different pulses overlapping or cumulative dose of laser exposure in irradiated area. Fabrication of shallow groove on the surface is also demonstrated.

Micro-deposition of an aluminum film of 500-nm thickness on a quartz substrate was demonstrated by laser-induced forward transfer (LIFT) using a femtosecond laser pulse. With the help of atomic force microscopy (AFM) and scanning electron microscopy (SEM), the dependence of the morphology of deposited aluminum film on the irradiated laser pulse energy was investigated. As the laser fluence was slightly above the threshold fluence, the higher pressure of plasma for the thicker film made the free surface of solid phase burst out, which resulted in that not only the solid material was sputtered but also the deposited film in the liquid state was made irregularly.

采用有限差分法对约化后的双温方程进行数值模拟．研究了飞秒激光与金属铜相互作用时，脉冲形状对烧蚀结果的影响．结果表明：脉冲能量确定时，脉冲形状对烧蚀结果影响不大；多脉冲作用时，脉冲重复频率只有在一定范围内(随材料属性改变)，脉冲间的热累积效应才存在；对传导性好的金属材料，热累积效应不明显．并实验证实了上述结果．

Ablation process of 1-kHz femtosecond lasers (pulse duration of 148 fs, wavelength of 775 nm) of Au film on silica substrates is studied. The thresholds for single and multi pulses can be obtained directly from the relation between the squared diameter D2 of the ablated craters and the laser fluence 'phi'0. From the plot of the accumulated laser fluence N'phi'_(th)(N) and the number of laser pulses N, incubation coefficient of Au film is obtained to be 0.765. Some experimental data obtained around the single pulse threshold are in good agreement with the theoretical calculation.

Ablation experiments with femtosecond (fs) laser pulse (pulse duration 37 fs, wavelength 800 nm) on organic polymers have been performed in air. The ablation threshold is found to be only several nanojoules. The diameters of the dots ablated in the organic polymers are influenced by the laser fluence and the number of laser pulses. It is observed that heat is diffused in a threadlike manner in all directions around the central focus region.Explanations of the observed phenomena are resented. A one-dimensional waveguide is also ablated in the organic polymers.