Free-electron lasers and their applications

We review the classical theory of the free-electron laser and discuss possible applications in laser fusion, laser-induced chemistry, biochemistry, and solid-state physics. The possibility of using optical wigglers to reach the VUV and soft X-ray regimes is also analysed.     

Infra-red lasers and their applications

Properties and applications of infra-red lasers are reviewed, with particular emphasis on those likely to be fundametnally important in energy production, materials and data processing.     

Erbium glass lasers and their applications

In this paper results of experimental investigations into erbium glass lasers and their likely applications are discussed. Regularities of the inversion energy accumulation, also as channels of energy losses, are covered in detail. Different erbium lasers, both flashtube and neodymium laser-pumped, are compared. Parameters of some erbium laser glasses are presented, including the new LGS-E7, which requires a smaller pumping energy density (less than 100–200 J cm^-2). Test data from experimental models are summarized.     

Far-infrared free-electron lasers and their applications

Free-electron lasers based on radio-frequency linear accelerators provide an important source of far-infrared radiation which allow exciting experiments that cannot be performed in any other way. Facilities such as FELIX (Nieuwegein, The Netherlands), JFEL (Newport News VA, USA), FELBE (Dresden, Germany), CLIO (Paris, France) and others provide mid- and far-infrared output in picosecond pulses with micro-joules of energy. They give continuous, wide tuning in far-IR for resonant pumping of discrete transitions (with simultaneous coverage of mid-IR) from around 3 to 250 μm wavelength. This enables time-resolved spectroscopy, non-linear optics and spectroscopy of weak absorptions. They have been applied to a wide variety of problems in condensed matter physics, physical chemistry and biophysics. We review the physics applications of these sources.     

Tunable infra-red lasers and their applications to air pollution measurements

This paper describes a number of tunable infra-red lasers and techniques employing them for the detection and monitoring of gaseous air pollutants. Recent progress in the development of lasers that can be matched to characteristic infra-red absorption or emission lines of certain pollutants suggest wide potential application for sensitive specific monitoring. Examples to be described include highly-specific point-sampling,in situ source monitoring, ambient air monitoring, resonance fluorescence, and remote heterodyne detection.This work was supported by the Environmental Protection Agency.     

X射线自由电子激光的原理和在生物分子结构测定研究中的应用

X射线具有短波长和强穿透能力,利用电子对X射线的散射能够研究材料和分子的精密内部结构。信号的质量高度依赖于X射线发射源。2009年,美国能源部下属的斯坦福线性加速器中心国家实验室建成世界上第一台具有原子分辨率能力的X射线自由电子激光设施(LCLS),从此X射线进入激光时代,人类所能使用的X射线的峰值亮度比最强的同步辐射X射线光源提高了100亿倍。文章简要介绍了X射线自由电子激光的发展历程、产生原理和特性,并结合具体实验研究对如何应用X射线激光研究生物学领域的分子结构和动态变化进行总结。     

超强超短激光及其应用新进展

超强超短激光能在实验室内创造出前所未有的超高能量密度、超强电磁场和超快时间尺度综合性极端物理条件,在激光加速、阿秒科学、激光聚变、等离子体物理、核物理与核医学、原子分子物理、实验室天体物理、高能物理等领域具有重大应用价值,是当前国际科技重要前沿与竞争重点领域之一。文章简述了超强超短激光的基本概念,最新研究进展与未来发展趋势,以及我国超强超短激光的研究现状,最后简述了超强超短激光的应用示例。     

Synthetic methods for polyamine linkers and their application to combinatorial chemistry

Summary Polyamines and polyamine conjugates display a diverse range of important biological functions, ranging from antibiotics to immunosuppressants and glutamate receptor antagonists. For these reasons, polyamines provide an excellent template/scaffold for combinatorial chemistry. In this paper we present methods for the solid-phase immobilisation of polyamines for use in synthetic and combinatorial chemistry and describe how they have been employed in the preparation of a number of important polyamine conjugates and polyamine libraries. Thus, we have designed, synthesised and utilised a number of polyamine linkers for both solution and resin screening combinatorial application.     

High-pressure continuously tunable CO2 lasers and molecular laser isotope separation

The acronym MLIS (molecular laser isotope separation) defines the laser process whereby the isotopes of uranium can be separated by mid-infrared laser/s when the molecule employed is UF₆. The theoretical and spectroscopical data to configure and enable experiments and demonstrations in the laboratory is adequate. However, the engineering and commercial aspects require innovative technology solutions that are not presently available in the literature on these topics. This paper is an overview of the most salient features of MLIS and its potential utility at an industrial level.     

Infrared laser chemistry and the dynamics of molecular multiphoton excitation

Recent progress in IR-laser chemistry is reviewed. Particular emphasis is placed upon the understanding of the photophysical primary processes of IR-multiphoton excitation in laser chemistry. The available experimental evidence on the main mechanisms of these processes is summarized and compared to various theoretical views. The connection to results on intramolecular rovibrational dynamics from high resolution spectroscopy is established. Some recent quantitative rate data are reviewed in relation to simple theoretical estimates. Several applications of IR-laser chemistry are mentioned, including laser isotope separation and mode selective chemistry. We conclude with a particularly striking potential application of laser chemistry to fundamental aspects of physics, the determination of the parity violating weak nuclear force in polyatomic molecules.     

Time history of laser power pulses from molecular gas lasers

The leading edge of laser power pulses is shown to be described by one exponential function in molecular gas lasers with a directly pumped upper laser level and by a sum of two exponential functions in lasers with an indirectly pumped upper laser level.     

Fundamental aspects of FT-ICR and applications to chemistry

Fourier transform ion cyclotron resonance (FT-ICR) spectroscopy, a modern form of mass spectrometry whose advantages were first demonstrated in our laboratory in 1974, is characterized by ultrahigh mass resolution, wide mass range, high speed and automatic mass calibration. Together with the FT-ICR double resonance experiment, these advantages make FT-ICR a powerful technique for studying complex ion/molecule reaction pathways and for general problems in analytical mass spectrometry. In addition, the high resolution principles of FT-ICR have been widely adopted around the world for precise mass measurements of nuclides.     

薄膜和多层膜的X射线散射方法与应用

文章主要介绍了几种X射线散射技术，包括X射线小角反射技术、X射线漫散射技术、掠入射X射线衍射和多晶薄膜的小角衍射技术。通过具体的事例说明这些X射线散射方法在薄膜研究中的应用。     

薄膜和多层膜的X射线散射方法与应用

文章主要介绍了几种X射线散射技术,包括X射线小角反射技术、X射线漫散射技术、掠入射X射线衍射和多晶薄膜的小角衍射技术。通过具体的事例说明这些X射线散射方法在薄膜研究中的应用。     

New lasers and laser schemes

Conclusion We have demonstrated the existence of an anomalous polarization coupling mechanism present in the injection locked TEA CO₂ laser. As a direct consequence of this work, a new injection technique has been formulated which permits efficient injection coupling and maximises energy extraction whilst eliminating the detrimental optical feedback effects to which other injection locking systems are prone.Supported by the Office of Naval Research and the National Science Foundation     

Excimer lasers and laser systems

The results of the experimental study of UV lasers and laser systems pumped by different methods are presented. Two lasers were pumped by electron beams from Marx generators. Three lasers were pumped by transverse discharge with UV preionization. An XeCl laser pumped by electric discharge using a generator with inductive energy storage and semiconducting opening switch is investigated. The highest laser radiation energies of 2000, 90, and 0.7 J have been obtained at 5=308, 249, and 222 nm, respectively. The amplification of the laser beam from the master oscillator under conditions of strong amplified spontaneous emission is considered. In particular, formation of the output from an amplifier in the wings of the XeCl laser band and in the case of a large-aperture XeCl amplifier are investigated. The output beam divergence in these experiments was measured to be ~10^-4 rad.