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It is predicted that the optical force experienced by a dielectric particle excited resonantly by a surface wave can be directed opposite to the incident power flow when the exciting wave is a backward one. This is consistent with the electromagnetic momentum flow of the backward wave being directed opposite to the power flow. The magnitude of the force can(More)
It is shown that a wavelength-sized dielectric particle can form a resonant state with the below-cutoff mode of a waveguide even for rather small values of the refractive index contrast between the particle and the background. The excitation of the resonant state creates the propelling force twice the momentum flow of the incident mode, and the particle is(More)
Near field optical manipulation of microparticles is usually considered a nonresonant effect determined by the momentum conservation law. In this work we study optical propelling of polystyrene microspheres with diameters from 3 to 20 μm in the evanescent field produced by water immersed tapered microfibers. We show that the velocity of propelling(More)
Light pressure effect has been discovered long ago and has been used as an optical method to manipulate micro- and nanoparticles. It is usually considered as a nonresonant effect determined by the transfer of the momentum of light. However, recently we have observed that large polystyrene microspheres of 15 - 20 μm diameters supporting high quality(More)
The Cherenkov wakes excited by intense laser drivers in a perpendicularly magnetized plasma are a potential source of high-power terahertz radiation. We present a two-dimensional (2D) theory of the emission of magnetized wakes excited by a short laser pulse. The 2D model reveals the important role of the transverse size of the laser pulse missed in previous(More)
Scattering of a standing surface plasmon by rapid ionization in a semiconductor is investigated. We show that, for a standing plasmon, in contrast with a traveling plasmon, the scattering depends on the plasmon phase at the moment of ionization. By changing the moment of ionization, we can control the energy that is transferred into newly excited modes,(More)
Despite all the success with developing super-resolution imaging techniques, the Abbe limit poses a severe fundamental restriction on the resolution of far-field imaging systems based on diffraction of light. Imaging with contact microlenses, such as microspheres or microfibers, can increase the resolution by a factor of two beyond the Abbe limit. The(More)
We show that the usual Fresnel formulas for a free-propagating pulse are not applicable for a forced terahertz electromagnetic pulse supported by an optical pulse at the end of a nonlinear crystal. The correct linear reflection and transmission coefficients that we derive show that such pulses can experience a gain or loss at the boundary. This energy(More)
Clusters of circular resonators with coupled whispering gallery modes (WGMs) have interesting spectral and optical transport properties. We employ the finite-difference time-domain method to numerically study these properties. Using evanescent couplers, we show that various configurations of cavities display distinct spectral features (mode splitting) in(More)
Resonances can give rise to the appearance of large and highly frequency selective optical forces on microparticles. The forces are studied in two cases: when intrinsic resonances in dielectric particles exist and when resonances are created as a result of the interaction of particles with waveguides. The resonant forces can be used for high accuracy(More)