激光束

Creative research has been carried in the technologies of temporal pulse shaping, spatial intensity shaping, angular spectrum dispersion, and wave front control, which cover four parameters of time, amplitude, spectrum and phase that describe the characteristics of a laser beam.

以表征激光束特性的时间、振幅、光谱、位相等四个信息参量为对象，创新性地研究了脉沖时域整形技术、光强空间整形技术、光谱角色散技术和波前控制技术。

Spectrum control technology and its application researchBasic theory of smoothing by spectral dispersion in high-power laser system was studied. Periodical frequency modulation was obtained by chirped pulse stacking, and novel special gratings were proposed here to obtain angular spectral dispersion and temporal smoothing of focal spot.

并在国际上首次成功地应用于激光聚变高功率激光系统中。3、激光脉冲光谱控制技术及应用研究研究了高功率激光光谱色散平滑的基本理论，提出利用堆积啁啾脉冲的周期性光谱调制特性和新颖特殊光栅实现光谱角色散和激光束远场焦斑的时间平滑。

In this paper, firstly we researched the relationships of the communicating distanceand the channel characteristic, the effect of the multiple scattering to the laserpropagation, the requirement of the laser communication to the ATP system and theway to determine the angular dispersion and receive field of view. It is proved that inlight haze weather, letting the input and output laser\'s wavelength are diferrent witheach other, after passing by the filter, it can avoid backward scattering effectually andfor the communication within 15km, the influence of the multiple scattering inatmosphere can be ignored.

论文对通信距离与信道特性、多次散射对光传输的影响、无线激光通信对ATP带宽的需求以及光束发散角和接收视场角等重要系统性能参数和指标进行了分析和研究，证明了在轻霾天气状态下，使系统中两终端发送的激光束波长各不相同，经过光束滤波，可以有效地消除后向散射干扰；在15km的通信距离范围内，大气中的多次散射对无线激光通信光传输的影响可以忽略。

We firstly bring forward and realize technologies of arbitrarily shaping laser pulse in the time domain by chirped pulse stacking, programmablely shaping spatial intensity by crystal liquid diaphragm, focused spot smoothing using angular spectrum dispersion by special gratings and detecting and compensating the small patch wave front aberration. Precise, programmable, efficient and \'all parameters\' condition of high power laser system has been obtained.

首次提出并实现了啁啾脉冲堆积型的时间波形任意整形；液晶光阀可编程光强空间整形；特殊光栅光谱角色散焦斑束平滑和小尺度波前畸变的探测和补偿，从而对高功率激光系统的激光束实现了高精度、可编程、有效的"全息"控制。

And,some comparisons between beam splitter and fiber coupler were made when they were used for coherent combining,and the correctness of the obtained phase-shift relationship was also verified.

比较了分束器与光纤耦合器在激光束相干合成应用中的一些特性，并验证了所得相移关系式的正确性。

Reasonable baseline is one of the key matter in the straightness measurement. Two schemes of the measuring basis are advanced in the paper--tensile spring and laser beam, based on the request and character of guide-ways straightness measurement. In early study, we come to the conclusion by theoretical analysis and experiment that the laser beam basis has more advantage in development and accuracy.

合理的直线基准是实现直线度测量的一项关键内容，本文首先针对导轨直线度的测量要求与特点，提出了张丝与准直激光束两个测量基准方案，并在前期研究中通过理论分析与大量的实验对比得出结论：激光束在系统实现及测量精度等方面均具有更高的优越性。

The theoretical curve of the sound directivity which is influenced by the laser beam radius is drawn by the numerical method and drawing software.

讨论了激光束半径对声源指向性的影响，并用数值计算方法和绘图软件，画出激光束半径对声源指向性影响的理论曲线图。

Mobile positioning system or dynamic table so that the laser head is cutting material in the system-driven subcapital high speed, laser head from the light source and cutting heads, light source produces a very short wavelength focused laser beam, laser beam through cutting heads, vertically focused the material being cut on the surface, heating and melting, evaporation is cutting material, resulting in the closure of Lancing, slotted openings formation pads.

移动定位系统妪动工作台或激光头，使得被切割材料在系统驱动头下高速运动，激光头由光源部分和切割头组成，光源部分产生波长很短的聚焦激光束，激光束通过切割头，垂直聚焦在被切割的材料表面上，加热、融化、蒸发被切割材料，形成切缝，闭合的切缝形成焊盘开孔。

At present, laser process technology develops fast, since a laser light can obtain many good characteristics such as good direction, high energy density to focus the beam at a micrometer level, small pulse width ranging from dozens of Nanoseconds to dozens of Picoseconds, heating material immediately, decreasing heat effect on materials and so on.

由于激光束具有良好的方向性和高能量密度，可将光束聚焦到微米量级；由于激光束的脉冲宽度可达数十纳秒到数十皮秒，能够快速加热，对材料的热影响效应减小；因此，激光的以上优点为微加工提供了有利的条件，同时也促使激光加工技术迅速发展。

This paper introduces the studies of the ultra-short Thomson scattering X-ray source at the accelerator laboratory of Tsinghua University in recent years. Properties such as the photon yield,the pulse length and time jitter of the produced photon pulse were predicted theoretically from the parameters of the electron bunch and the laser pulse,and the scattering angle. Preliminary experiments were successfully carried out with a 16 MeV backward-traveling-wave accelerator and the ns-Q switched laser provided by China Academy of Engineering Physics. This paper also introduces the 1.6-cell electron gun that was fabricated on site and the experiment with high RF power including the measurement of the electron bunche parameters. Based on these,we have designed an X-ray source,which is now under construction.

介绍了清华大学加速器实验室近年来关于汤姆逊散射超短X射线源的研究工作；研究了在任意散射角度下电子束参数和激光束参数对散射光子参数的影响，给出了散射光子的参数如光子产额、脉冲长度、时间抖动等与电子束参数、激光束参数和散射角度的关系；利用实验室已有的16 MeV反波行波加速器与中国工程物理研究院激光聚变研究中心提供的ns调Q激光搭建了汤姆逊散射初步实验平台并开展了实验研究；加工了1.6-cell光阴极微波电子枪，搭建了高功率实验平台，对产生的电子束参数进行了初步测量；对汤姆逊散射超短X射线源进行了设计并开展了相关的平台建设工作，对产生的X射线脉冲参数进行了模拟。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。