@ARTICLE\{IMM2000-0325,
    author       = "L. Berg\'{e} and O. Bang and W. Krolikowski",
    title        = "Influence of four-wave mixing and walk-off on the self-focusing of coupled waves",
    year         = "2000",
    month        = "apr",
    pages        = "3302-3305",
    journal      = "Physical Review Letters",
    volume       = "84",
    editor       = "",
    number       = "15",
    publisher    = "The American Physical Society",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/325-full.html",
    abstract     = "Four-wave mixing and walk-off between two optical beams are investigated for focusing Kerr media. It is shown that four-wave mixing reinforces the self-focusing of mutually trapped waves by lowering their power threshold for collapse, only when their phase mismatch is small. On the contrary, walk-off inhibits the collapse by detrapping the beams, whose partial centroids experience nonlinear oscillations."
}