Preface

The studies of ultrashort laser pulse interactions with single atoms, molecules, nanoparticles and condensed matter is a hot topic of modern physics, since the obtained results stimulate the development of fundamental principles of light-matter interaction and, at the same time, find the wide area of practical applications.

This volume contains the contributions devoted both to the discussion of general principles and fundamental experiments, as well as the different practical applications. The content of the volume has been divided into the two sections, however, this division is rather formal because the most of papers concern with the general problems and simultaneously provide the elegant proposals of practical applications.

The methods of ultrashort high-energy X ray pulse producing based on the use of femtosecond laser pulses are discussed and the available parameters are compared with the X-ray pulse parameters obtained in the large facilities like as Synchrotron or X-ray Free electron lasers (X-FEL) (chapter 1). An overview of the modern status of research on laser-driven plasma-based electron acceleration is presented. The basic principles, recent achievements, and possible applications are discussed in chapter 2. It is demonstrated that the use of well-controlled laser fields offer an exquisite control tool over atomic and molecular internal and external states, including laser cooling and trapping, coherent manipulation of atomic quantum states and in particular various techniques used for quantum information applications, atomic spectroscopy (chapter 3). Progress in the technology of short laser pulse amplification made shortpulse, high-repetition-rate, multi-terawatt laser facilities available to a large community of researchers. These new instruments revolutionized experiments in nonlinear optics, and enabled a design of compact, plasma-based sources of x-rays, electrons, ions, etc. The physics of the processes occurring in plasma produced by ultrahigh intensity femtosecond laser pulses is discussed in chapters 4 and 5. Timeresolved laser spectroscopy as an important method for extracting optical and transport parameters of semiconductors and semiconductor nanostructures is discussed in chapter 6. The novel applications of laser methods in atomic collisions, cold plasmas and cold atom physics are discussed in chapter 7. The review the current progress of time resolved x-ray spectroscopy based on the use of femtosecond and attosecond x-ray pulses is given in chapter 8. Some examples of successful applications of the ultrafast time resolved spectroscopy methods in material science and solid state

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physics are discussed in chapter 9. The new approach in the theory of light-atom interaction is discussed in chapter 10. The main benefits of the proposed approach are in the following. Firstly, the approach is free of any limitations on the laser field strength (in comparison with the intra-atomic field strength). Secondly, the arbitrary orientation of atomic electron angular momentum and polarization vector of electromagnetic wave is the primordial concept of approach.

The papers of the volume reflect the results of research on the application of pulsedlight sources in optical communication, quantum information processing (chapter 11), and quantum networks (chapter 13). The recent achievements in the study of the fast photoresponse of superconductor materials for detecting the ultrafast laser pulse are discussed in chapter 12. The techniques of THz pulse generation with the help of ultrashort laser pulses are discussed in chapter 14. The brief description of currently most important applications of laser pulses in photovoltaic effect is given in chapter 15. The authors concentrate on a description of recent developments and survey the current state of affairs regarding the physics and the methods currently used for analyzing the experiments. The chapter 16 is devoted to the photoacoutic tomography as a new imaging method which is attractive for medicine and biology because it is capable to provide a three dimensional image of electromagnetic absorption properties of biological tissue – which is dependent of the used wavelength - without ionizing radiation. The liquid phase photoelectron spectroscopy with high time-resolution realized with the combination of powerful technologies such as photoelectron spectroscopy near volatile liquid interfaces in vacuum, ultrafast pump-probe spectroscopy, and table-top high harmonics generation of soft X-ray radiation is discussed in chapter 17.

> **Anatoli V. Andreev**  Professor of Physics M.V.Lomonosov Moscow State University Moscow, Russia
