Seminários

Colóquios do IF-UFF

Na próxima terça-feira (dia 22/03) às 11 horas teremos o colóquio do prof. Dr. Tito Mendonça (Universidade de Lisboa, Portugal) na sala 201.

Segue o título e resumo do colóquio.


A comissão.

TITLE: TWISTED LASER BEAMS

Abstract
We give an overview of the physics of twisted laser beams, which carry a finite amount of orbital angular momentum (OAM). In the paraxial approximation, these beams can be described by Laguerre-Gauss (LG) functions. They have been explored in nonlinear and quantum optics during the last twenty years, but recently the problem emerged in plasma physics, where different kinds of new processes have been identified. Qualitative changes occur in plasmas, because not only electromagnetic but also electrostatic waves (such as twisted plasmons and phonons) can be excited. In particular, these electrostatic waves with OAM display qualitatively new kinetic properties, including a generalized Landau damping.
We also discuss the changes introduced by OAM on the nonlinear processes associated with intense and short laser pulses interaction with a target. They lead to the formation of exotic forms of wakefields, such as donut wakes, plasmon springs, and fractional vortices. Their impact on particle acceleration, nonlinear decay processes, magnetic field generation and laser amplification is considered. Other nonlinear effects associated with laser OAM propagation in plasmas are also considered, such as: Raman and Brillouin stimulated backscattering, inverse Faraday effect with linear polarization, radiation pressure and high-harmonic generation.