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A laser-based security technique called Laser Surface Authentication (LSA) is described in which diffuse laser scattering is used as a probe of the naturally-occurring randomness present in virtually all surfaces. LSA brings the principles of biometric identification currently used in human fingerprint- or iris-recognition to the world of inanimate objects such as paper documents, plastic cards, high value branded products and a range of other things that are commonly counterfeited or smuggled. [ABSTRACT FROM AUTHOR]

Russian science icon, Pyotr Lebedev, is well known for first proving the existence of light pressure by measuring its action on both solids and gases. His experiments are discussed here as well as comparison with later, independent light-pressure measurements in solids by Nichols and Hull and European scientists. These light pressure experiments were the first steps of Lebedev's programme in unravelling the effects of light on atoms and molecules, as well as the intermolecular forces due to radiation. His students completed this programme and realised his dream of launching a research institute. The Lebedev Physical Institute founded by Vavilov, throughout its history described here, set great scientific milestones. Seven Nobel laureates used to work in this institute: Cherenkov, Frank, Tamm (1958), Basov and Prokhorov (1964), Sakharov (1975), Ginzburg (2003). Mandelstam is named 'the forefather' of theoretical physics in Moscow. Letokhov is one more prominent figure who extended Lebedev's light-pressure experiments and demonstrated experimentally for the first time the laser cooling of atoms. [ABSTRACT FROM AUTHOR]

In this paper we describe experiments conducted with high-power lasers that are attempting to replicate, for a very short time and in miniature, conditions found in the Sun. Experiments to date have reached conditions in the outer part of the Sun. To reach the Sun's centre requires compression of material to very much greater than solid density and heating to over ten million degrees. To achieve this, a new class of experiments and a new generation of high-power lasers are required. [ABSTRACT FROM AUTHOR]

This work describes the atomic route to laser isotope separation. This is a process which uses intense pulsed lasers to photoionize one isotopic species of a chemical element, after which these ions are extracted electromagnetically. The paper describes only the isotopic enrichment of uranium for nuclear fuel cycles. It makes brief mention of the traditional cascade processes used at present, and then turns to the atomic physics of laser photoionization. The principles of the laser isotope separation process, important spectroscopic experiments and considerations which determine the design of a plant are described. This review concentrates on the laser ionization process, few details of vaporization of uranium metal or the extraction of ions are given. [ABSTRACT FROM AUTHOR]

This paper provides an introduction to methods for stabilizing continuous-wave single-mode lasers and discusses the fundamental limits on the maximum stability achievable. Both passive and active methods are described, the latter being treated by separating the problems of error discrimination and error correction. Means of evaluating stability are briefly reviewed and examples of applications of stabilized lasers are presented. [ABSTRACT FROM AUTHOR]

Developments in basic physics are commonly related to advances in technology and in measurement techniques. Sometimes new methods of measurement open up new branches of knowledge and at other times the new techniques follow. One example is the development of high-power frequency tunable dye-lasers which has permitted the selective excitation of atoms and molecules and the recording of absorption spectra from exited states. With the extension of tunable lasers into the ultraviolet these new spectroscopic techniques can be applied to a wide range of transitions. The recent advances in direct time measurements in the picosecond range provide a second example. These have been made possible by the availability of intense ultra-short pulses of light from mode-locked lasers. It is thus now possible to investigate on a picosecond time-scale the interactions of light with matter. The present state of the art in both of these fields is reviewed with particular reference to electron optical streak-camera measurements and to experiments employing frequency-tunable, picosecond pulses from mode-locked dye lasers. Applications considered include compression of matter to very high densities and temperatures, for thermo-nuclear fusion, and photo-chemistry.
This paper is an updated version of a Plenary Session Lecture at the Centenary Meeting of the Institute of Physics and the French Physical Society at Jersey (Franco-British Centenary Conference) April 1974. [ABSTRACT FROM AUTHOR]

Researches on the electron-positron pair production in the presence of the intense laser field are reviewed, motivated by the theoretical importance of the nonperturbative QED problem and the worldwide development of high power laser facilities. According to the distinct experimental requirements and theoretical methods, two types of pair production are elaborated, which are, respectively, pair production in the combination of a seed particle and the strong laser, and vacuum pair production without a seed particle. The origin of the nonperturbative problem caused by the strong field is analyzed. The main ideas, realisation, achievements, validity, challenges and bottleneck problems of the nonperturbative methods developed for each type of the pair production problem are discussed. [ABSTRACT FROM AUTHOR]

With the recent advances in laser technology, experimental investigation of radiation reaction phenomena is at last becoming a realistic prospect. A pedagogical introduction to electromagnetic radiation reaction is given, with the emphasis on matter driven by ultra-intense lasers. Single-particle, multi-particle, classical and quantum aspects are all addressed. [ABSTRACT FROM AUTHOR]

In the summer of 1961, a landmark experiment was performed at the University of Michigan in which optical second harmonic generation was observed for the first time. This event 50 years ago marked the birth of modern nonlinear optics, and this article celebrates the first half century of what is now a vast and vibrant field at the cutting edge of laser technology. The focus is mainly on nonlinear optics in the 1960s partly because it is appropriate in this anniversary year to remember the genesis of the field, but also because such remarkable progress was made in the first few years. However, a brief review of where things stand at present is included, and one aspect of the field today (high harmonic generation) is taken as a representative example of an area of nonlinear optics that lies at the current frontier of knowledge. [ABSTRACT FROM AUTHOR]

The study, preservation and restoration of cultural heritage materials and objects are crucial for obtaining important historical information, maintaining their aesthetic appeal or understanding early technologies. The unique, highly diverse character of cultural heritage items impose the need for rigorous scientific approaches, often incorporating non-invasive, mobile or remote technologies and the valorisation of objects and preservation methodologies. Here, we overview the fundamental aspects in the use of lasers for the analysis and restoration of artworks. For the former purpose, emphasis is placed on the use of Raman and Laser-Induced-Breakdown spectroscopies, both of which have been of increasing importance in the field of Cultural Heritage. The use of lasers for the restoration of artworks, in particular of painted artworks and parchments are described. Studies on model polymeric systems, as well as realistic artefacts, have permitted detailed assessment of the mechanisms and of the effects of the procedure. Finally, we provide an assessment of the potential of new laser-based technologies and techniques for the purpose of conservation/restoration of cultural objects. [ABSTRACT FROM AUTHOR]

Brownian motors are devices which ‘rectify’ Brownian motion, i.e. they can generate a current of particles out of unbiased fluctuations. Brownian motors are important for the understanding of molecular motors, and are also promising for the realization of new nano-electronic devices. Among the different systems that can be used to study Brownian motors, cold atoms in optical lattices are quite an unusual one: there is no thermal bath and both the potential and the fluctuations are determined by laser fields. In this article recent experimental implementations of Brownian motors using cold atoms in optical lattices are reviewed. [ABSTRACT FROM AUTHOR]