Interference Effects in the Conical Emission of Femtosecond Filament in Fused Silica
A. E. Dormidonov, V. P. Kandidov, V. O. Kompanets+, S. V. Chekalin+
M.V. Lomonosov Moscow State University, Physics Department, 119991 Moscow, Russia
+Institute of Spectroscopy RAS, 142190 Troitsk, Moscow Region, Russia
Abstract
It is shown both experimentally and theoretically that
interference effects play the key role in the formation of frequency-angular
spectrum of the filament conical emission. For the first time we
investigated experimentally the transformation of the conical emission
frequency-angular spectrum with increasing of the filament length inside
fused silica. We discovered the appearance of fine structure of the conical
emission rings produced by lengthy filament. It is shown that the conical
emission frequency-angular spectrum is produced by interference of coherent
radiation from one or several moving point sources in the filament. The shape
of the conical emission spectrum depends on the medium material dispersion,
the spectrum structure is determined by length and relative location of
filament emitting regions.