相关论文: Bright quasi-phasematched soft x-ray harmonic radi…

We report on simultaneous X-ray and radio observations of the mode-switching pulsar PSR B0943+10 obtained with the XMM-Newton satellite and the LOFAR, LWA and Arecibo radio telescopes in November 2014. We confirm the synchronous X-ray/radio…

We investigate dynamics of atomic and molecular systems exposed to intense, shaped chaotic fields and a weak femtosecond laser pulse theoretically. As a prototype example, the photoionization of a hydrogen atom is considered in detail. The…

In this paper, we present the analytical theory of attosecond pulse formation via optical modulation of an active medium of the hydrogen-like C5+ plasma-based X-ray laser at 3.4 nm wavelength in the "water window" range, taking into account…

We report transient quasi-periodic oscillations (QPOs) on minute timescales in relativistic, radiative models of the galactic center source Sgr A*. The QPOs result from nonaxisymmetric $m=1$ structure in the accretion flow excited by MHD…

The main quasi-particle characteristics of the one-dimensional polaron are estimated within and beyond the most general Gaussian approximation at arbitrary electron-phonon coupling. We have derived explicitly the ground-state energy and the…

The X-ray quasi-periodic oscillation (QPO) seen in RE J1034+396 is so far unique amongst AGN. Here we look at the another unique feature of RE J1034+396, namely its huge soft X-ray excess, to see if this is related in any way to the…

We propose a new scheme to generate high-brightness and temporal coherent soft x-ray radiation in a seeded free-electron laser. The proposed scheme is based the coherent harmonic generation (CHG) and superradiant principles. A CHG scheme is…

The article reports on light enhancement by structural resonances in linear periodic arrays of identical dielectric elements. As the basic elements both spheres and rods with circular cross section have been considered. In either case, it…

High-gain optical parametric amplification is an important nonlinear process used both as a source of coherent infrared light and as a source of nonclassical light. In this work, we experimentally demonstrate an approach to optical…

Novel table-top sources of extreme-ultraviolet light based on high-harmonic generation yield unique insight into the fundamental properties of molecules, nanomaterials, or correlated solids, and enable advanced applications in imaging or…

Thanks to progress in optics in the past two decades, it is possible to create photons carrying well-defined non-zero orbital angular momentum (OAM). Boosting these photons into high-energy range preserving their OAM seems feasible.…

Free-electron lasers (FELs) generate the brightest coherent X-ray pulses available, enabling atomic-resolution and femtosecond-timescale studies across physics, chemistry, and biology. Realising their full potential at extreme peak powers…

Two kinds of processes could occur during the flare decay phase: processes of energy release or processes of energy relaxation. Quasi-periodic pulsations (QPPs) of the broadband emission are a good tool for the verification of mechanisms.…

High-order frequency mixing in graphene using a two-color radiation field consisting of the fundamental and the second harmonic fields of an ultrashort linearly polarized laser pulse is studied. It is shown that the harmonics originated…

High-order harmonic generation in multiphoton ionization regime is studied theoretically to examine the resonant effects of the generating particle. We solve the time-dependent Schr\"odinger equation for In+ in the laser field by expanding…

The balance of the linear photon momentum in multiphoton ionization is studied experimentally. In the experiment argon and neon atoms are singly ionized by circularly polarized laser pulses with a wavelength of 800 nm and 1400 nm in the…

The quark potential model for mesons and its extension for hybrid mesons are used to study the effects of radial excitations on the masses, sizes and radial wave functions at the origin for conventional and hybrid charmonium mesons. These…

We show that electron betatron resonance acceleration by an ultra-intense ultra-short laser pulse in a near critical density plasma works as a high-brightness gamma-ray source. Compared with laser plasma X-ray sources in under-dense plasma,…

We propose and investigate the quasi-phase matched (QPM) nonlinear optical frequency conversion of optical vortices in periodically poled Lithium Niobate (PPLN). Laguerre-Gaussian (LG) modes are used to represent the orbital angular…

The surprising discovery by MAGIC of an intense, rapidly varying emission in the energy range 70 - 400 GeV from the flat spectrum radio quasar PKS 1222+216 represents a challenge for all interpretative scenarios. Indeed, in order to avoid…