Shock shells in Coulomb explosions of nanoclusters.

We predict that Coulomb explosion of a nanoscale cluster, which is ionized by high-intensity laser radiation and has a naturally occurring spatial density profile, will invariably produce shock waves. In most typical situations, two shocks, a leading and a trailing one, form a shock shell that eventually encompasses the entire cluster. Being the first example of shock waves on the nanometer scale, this phenomenon promises interesting effects and applications, including high-rate nuclear reactions inside each individual cluster.

Lasetron: a proposed source of powerful nuclear-time-scale electromagnetic bursts.

Electromagnetic bursts of substantial energy on a nuclear time scale of 10(-21)-10(-22) s [zeptosecond (zs) to sub-zs] can theoretically be generated by a perawatt or multiterawatt laser beam focused on a subwavelength-size solid particle or thin wire. Terawatt laser in a similar setup could be instrumental in reaching the subattosecond domain. The system may also generate a half-cycle pulse magnetic field on astrophysical scale up to approximately 10(6) T.

Electromagnetic bubble generation by half-cycle pulses.

Electromagnetic (EM) bubbles (EMB's), unipolar, super-short, and intense nonoscillating solitary pulses of EM radiation, can be generated in a gas of nonlinear atoms by available half-cycle pulses (HCP's). We investigate how EMB's characteristics (amplitude, length, formation distance, and total number) are controlled by the amplitude and length of originating HCP's. We also predict shocklike wave fronts in the multibubble regime.

Two-photon-induced fluorescence of biological markers based on optical fibers.

Optical fibers were used to induce fluorescence by means of two-photon absorption in fluorophores. The effect, studied in a solution of 4',6-diamidino-2-phenylindole, demonstrated that a single-mode fiber is a more efficient two-photon excitation source than a multimode fiber. This was shown with three different fibers.

Bright-bright 2pi solitons in stimulated Raman scattering.

We found conditions for excitation of bright-bright 2pi solitons in stimulated Raman scattering that involves nutation of population at Raman quantum levels, for two (laser-Stokes) and three (e.g., laser-Stokes-anti-Stokes) components. The soliton components at all participating frequencies are bright solitons of the same, Lorentzian, shape, in contrast to the well-known bright-dark soliton combination in stimulated Raman scattering.

Phase Matching For Large-scale Frequency Upconversion in Plasma.

We consider phase matching in the generation of very short-wavelength coherent radiation by nonlinear frequency upconversion in plasma and suggest some ways to improve phase matching in high-order harmonic generation. We obtain what are to our knowledge the first simple analytical expressions for a phase-matching factor in multiphoton mixing of an arbitrary order and demonstrate theoretically that high-order difference-frequency mixing in plasma could be, owing to its potential for phase-matching optimization, a more promising method of large-scale frequency upconversion than high-order harmonic generation.

Feasibility of x-ray resonant nonlinear effects in plasmas.

We demonstrate the feasibility of saturation-related third-order x-ray resonant nonlinear effects, in particular, absorption saturation and nonlinear refractive index in x-ray laser and laserlike Se XXV and Mo XXXIII plasmas as well as in other plasmas with lower degrees of ionization.

X-ray third-harmonic generation in plasmas of alkalilike ions.

We demonstrate theoretically the feasibility of x-ray near-resonant third-harmonic generation in a number of plasmas of Li- and Na-like ions as well as third-harmonic generation enhanced by phase matching using buffer plasmas.