激光、激光技术 激光参数测量

TN247 2005021017 基于单片机的激光远场光斑直接测量系统=Monolithic computer-based energy distribution direct measurement system of laser spot in field[刊,中]／朱震(中国人民解放 军63880部队．河南,洛阳(471003)),姚梅…//光电技术 应用．-2004,19(5)．-28—32 通过比较激光光斑远场直接测量与间接测量的优缺 点,提出使用单片机控制的探测器阵列进行远场光斑直接 测量。描述了系统结构,分析了关键技术,给出了主要程 序的框图。该系统能够测量激光光斑大小、形状、总能量、

其他应用

TN249//G306 2003053531我国激光技术领域成果专利保护亟待加强=On thepatent protection for laser technical achievements in ourcountry[刊,中]/杨哲(国家知识产权局专利局物理发明审查部.北京(100088))//中国激光.-2003,30(2).-189-192简述了激光技术发展的现状,详细介绍了国内外激光技术领域专利申请的状况,提出了我国激光技术成果专利保护方面的对策。表6参4(李瑞琴)

福建省对保安人员实行持证上岗和统一服装、标志

根据公安部有关保安服务业管理的规定，为了规范和加强保安从业人员的管理，最近省公安厅作出如下规定：一、严格保安从业人员管理全省保安服务公司和经公安机关批准纳入管理的自建保安组织的在岗保安从业人员，必须经地市公安机关统一培训考试合格后，核发《福建省保安员...

Generation of strong magnetic fields with a laser-driven coil

As a promising new way to generate a controllable strong magnetic field, laser-driven magnetic coils have attracted interest in many research fields. In 2013, a kilotesla level magnetic field was achieved at the Gekko XII laser facility with a capacitor-coil target. A similar approach has been adopted in a number of laboratories, with a variety of targets of different shapes. The peak strength of the magnetic field varies from a few tesla to kilotesla, with different spatio- temporal ranges. The differences are determined by the target geometry and the parameters of the incident laser. Here we present a review of the results of recent experimental studies of laser-driven magnetic field generation, as well as a discussion of the diagnostic techniques required for such rapidly changing magnetic fields. As an extension of the magnetic field generation, some applications are discussed.

Turbulent hydrodynamics experiments in high energy density plasmas： scientific case and preliminary results of the TurboHEDP project

The physics of compressible turbulence in high energy density(HED) plasmas is an unchartered experimental area.Simulations of compressible and radiative flows relevant for astrophysics rely mainly on subscale parameters. Therefore,we plan to perform turbulent hydrodynamics experiments in HED plasmas(TurboHEDP) in order to improve our understanding of such important phenomena for interest in both communities: laser plasma physics and astrophysics. We will focus on the physics of supernovae remnants which are complex structures subject to fluid instabilities such as the Rayleigh–Taylor and Kelvin–Helmholtz instabilities. The advent of megajoule laser facilities, like the National Ignition Facility and the Laser Megajoule, creates novel opportunities in laboratory astrophysics, as it provides unique platforms to study turbulent mixing flows in HED plasmas. Indeed, the physics requires accelerating targets over larger distances and longer time periods than previously achieved. In a preparatory phase, scaling from experiments at lower laser energies is used to guarantee the performance of future MJ experiments. This subscale experiments allow us to develop experimental skills and numerical tools in this new field of research, and are stepping stones to achieve our objectives on larger laser facilities. We review first in this paper recent advances in high energy density experiments devoted to laboratory astrophysics. Then we describe the necessary steps forward to commission an experimental platform devoted to turbulent hydrodynamics on a megajoule laser facility. Recent novel experimental results acquired on LULI2000, as well as supporting radiative hydrodynamics simulations, are presented. Together with the development of LiF detectors as transformative X-ray diagnostics, these preliminary results are promising on the way to achieve micrometric spatial resolution in turbulent HED physics experiments in the near future.

Optical forces of focused femtosecond laserpulses on nonlinear optical Rayleigh particles

The principle of optical trapping is conventionally based on the interaction of optical fields with linear-induced polarizations. However, the optical force originating from the nonlinear polarization becomes significant when nonlinear optical nanoparticles are trapped by femtosecond laser pulses. Herein we develop the time-averaged optical forces on a nonlinear optical nanoparticle using high-repetition-rate femtosecond laser pulses, based on the linear and nonlinear polarization effects. We investigate the dependence of the optical forces on the magnitudes and signs of the refractive nonlinearities. It is found that the self-focusing effect enhances the trapping ability, whereas the self-defocusing effect leads to the splitting of the potential well at the focal plane and destabilizes the optical trap. Our results show good agreement with the reported experimental observations and provide theoretical support for capturing nonlinear optical particles.

Valence state manipulation of Sm3＋ ions via a phase-shaped femtosecond laser field

The ability to manipulate the valence state conversion of rare-earth ions is crudal for their applications in color displays, optoelectronic devices, laser sources, and optical memory. The conventional femtosecond laser pulse has been shown to be a well-established tool for realizing the valence state conversion of rare-earth ions, although the valence state conversion efficiency is relatively low. Here, we first propose a femtosecond laser pulse shaping tech- nique for improving the valence state conversion effidency of rare-earth ions. Our experimental results demonstrate that the photoreduction emciency from Sm3＋ to Sm2＋ in Sm3＋-doped sodium aluminoborate glass using a zt phase step modulation can be comparable to that using a transform-limited femtosecond laser field, while the peak laser intensity is decreased by about 63%, which is very beneficial for improving the valence state conversion efficiency under the laser-induced damage threshold of the glass sample. Furthermore, we also theoretically develop a （2 ＋ 1） resonance-mediated three-photon absorption model to explain the modulation of the photoreduction efficiency from Sm3＋ to Sm2＋ under the π-shaped femtosecond laser field.