Confinement of electromagnetic energy into a single well-controlled oscillation of light is very important for generation of intense supercontinuum radiation. We find that the pulse breakup of few-cycle ultrashort laser pulses via resonant propagation effects can achieve this aim. By extracting such pulses and then focusing them to drive the He atoms, about $200\mathrm{eV}$ intense supercontinuum radiation can be generated, which is capable of supporting $\sim 20\text{attosecond}$ isolated pulse generation.

• Received 19 June 2008

DOI:https://doi.org/10.1103/PhysRevA.78.023836