Second harmonic generation and its interaction with relativistic plasma waves driven by forward Raman instability in underdense plasmas

Journal Article · Tue Apr 01 00:00:00 EST 1997 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.872201· OSTI ID:530918

Malka, V ^[1]; Modena, A; Najmudin, Z; Dangor, A E ^[2]; Clayton, C E; Marsh, K A; Joshi, C ^[3]; Danson, C; Neely, D; Walsh, F N ^[4]

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1. Laboratoire pour l`Utilisation des Lasers Intenses, Centre National de la Recherche Scientifique, Ecole Polytechnique, 91128 Palaiseau Cedex (France)
2. Imperial College, London (United Kingdom)
3. University of California at Los Angeles, Los Angeles, California 90024 (United States)
4. Rutherford Appleton Laboratory, Chilton (United Kingdom)

High conversion efficiency (0.1{percent}) into second harmonic light generated in the interaction of a short-pulse intense laser with underdense plasma has been observed. In this experiment the plasma is created by optical field ionization of hydrogen or helium gas. Second harmonic spectra observed in the forward direction show Stokes and anti-Stokes satellites. This is due to the interaction of the second harmonic light with large-amplitude relativistic plasma waves. Second harmonic images taken at 30{degree} from the propagation axis show that the radiation is generated over a length of a few times the Rayleigh length and that the origin of the second harmonic light is due to the radial electron density gradients created by the ionization process and the radial ponderomotive force. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 530918
• Journal Information: Physics of Plasmas, Vol. 4, Issue 4; Other Information: PBD: Apr 1997
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION
PLASMA WAVES
HARMONIC GENERATION
RELATIVISTIC PLASMA
RAMAN SPECTRA
PLASMA INSTABILITY
PLASMA DENSITY
RAMAN EFFECT
IMAGES
ELECTRON DENSITY
LIGHT TRANSMISSION
IONIZATION