Ghofraniha Neda, Conti Claudio, Ruocco Giancarlo, Trillo Stefano
Research Center SMC INFM-CNR, Università di Roma La Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy.
Phys Rev Lett. 2007 Jul 27;99(4):043903. doi: 10.1103/PhysRevLett.99.043903. Epub 2007 Jul 26.
We investigate the formation of collisionless shocks along the spatial profile of a Gaussian laser beam propagating in nonlocal nonlinear media. For defocusing nonlinearity the shock survives the smoothing effect of the nonlocal response, though its dynamics is qualitatively affected by the latter, whereas for focusing nonlinearity it dominates over filamentation. The patterns observed in a thermal defocusing medium are interpreted in the framework of our theory.