Propagation dynamics of intense femtosecond pulses: Multiple splittings, coalescence, and continuum generation

We present a scenario of (3 + 1)-dimensional spatiotemporal dynamics of fem tosecond laser pulses in a nonlinear media with normal dispersion. The sequ ence of events at progressively higher powers can be characterized as singl e splitting, multiple splitting, and coalescence. Self-focusing and splitti ng events are in general spatially separated. Experimental data confirm the above scenario, with measurements at the highest powers corresponding to t he regime of continuum generation. [S0031-9007(99)08469-0].