Enhanced spatiotemporal laser-beam smoothing in gas-jet plasmas.
Spatiotemporal smoothing of large-scale laser intensity fluctuations is observed for a laser beam focused into underdense helium plasmas. This smoothing is found to be severely enhanced when focusing the laser beam into a helium gas jet. In contrast to other experiments with preformed plasmas, the average and the peak laser intensities are well below the threshold for ponderomotive self-focusing. The coherence characteristics of the transmitted light are measured for various electron densities, and the smoothing effect is explained by multiple scattering of laser light on self-induced density perturbations.
Malka
V
V
Laboratoire d'Optique Appliquée, Ecole Nationale Supérieure des Techniques Avancées, Centre de la Recherche Scientifique UMR 7639, 91761 Palaiseau, France.
Faure
J
J
Hüller
S
S
Tikhonchuk
V T
VT
Weber
S
S
Amiranoff
F
F