Interference effects during the reradiation of ultrashort electromagnetic pulses by polyatomic systems
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Interference Effects during the Reradiation of Ultrashort Electromagnetic Pulses by Polyatomic Systems D. N. Makarov and V. I. Matveev* Lomonosov Northern (Arctic) Federal University, Arkhangelsk, 163002 Russia *Email: [email protected] Received April 21, 2013
Abstract—A theory of the reradiation of ultrashort electromagnetic pulses by arbitrary polyatomic systems of isolated complex atoms has been developed. The technique used allows the spatial inhomogeneity of the field of an ultrashort pulse and photon momenta in reradiation processes to be accurately taken into account. The angular distributions of the reradiation spectra have been obtained for an arbitrary number of atoms in the system. The processes of interference between the photon emission amplitudes are shown to give rise to char acteristic “diffraction” maxima. We consider onedimensional, twodimensional, and threedimensional rectangular lattices as examples as well as planar and cylindrical structures as models of planar nanosystems and nanotubes. DOI: 10.1134/S1063776113130153
1. INTRODUCTION The Xray diffraction by various kinds of periodic structures is commonly described as the scattering of plane waves with an infinite duration in time [1]. In contrast, the scattering of ultrashort electromagnetic pulses by such structures has been poorly studied until the present day. At the same time, such processes can supplement an Xray diffraction analysis with time resolved spectroscopy, which is associated, among other things, with attosecond spectroscopy and attosecond metrology. In attosecond physics [2–4], comparatively simple objects are commonly used as targets, and such an expansion of the objects of inves tigation seems necessary and follows the course [5, 6] of development of the physics of ultrashort processes. A comparatively small number of theoretical works are devoted to the reradiation of ultrashort pulses (see, e.g., [7] and references therein). The scattering of an ultrashort pulse by an atom was considered within the framework of a classical description in [8]. Compara tively recently, Astapenko [7, 9] developed a descrip tion of the scattering of an ultrashort electromagnetic pulse by a multielectron atom within the framework of a consistent quantummechanical approach based on the perturbation theory by taking into account the tar get excitation and the nondipole nature of the electro magnetic interaction, which is valid in a wide spectral range. The scattered radiation spectra were obtained for various ultrashort pulse durations. In principle, this approach is also applicable for attosecond or shorter pulses. In the cases of such a duration, however, an accurate allowance for the field of an ultrashort pulse is possible within the framework of the theory of sud den perturbations, which allows one to describe more
simply the rescattering processes [10] and to extend the theory to the simplest molecules [11, 12]. Recently, based on the theory [10], Matveev and Matrasulov [13] considered the reradiation of ul
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