3 HALF HARMONIC-GENERATION IN LASER-PLASMA INTERACTION - EVIDENCE FOR PLASMON PROPAGATION

Side emitted 3-omega/2 radiation was studied by interacting 1.064-mu-m laser light with plasmas obtained from exploding thin foils. Both focusing (f/8) and collecting (f/7) optics were designed in order to reduce the instrumental bandwidth of the 3-omega/2 spectrum. Time-resolved spectra and time-resolved images were obtained and analysed. All the observed spectral features, including the substantial lack of a <> component, the amount of red shift and bandwidth, are consistent with the Karttunen theory of half-integer harmonics generated in plasmas. This theory takes into account the propagation of omega/2 plasmons produced by <> and their coupling with laser light.