title: Generating coherent broadband continuum soft-x-ray radiation by attosecond ionization gating.
abstract: The current paradigm of isolated attosecond pulse production requires a few-cycle pulse as the driver for high-harmonic generation that has a cosine-like electric field stabilized with respect to the peak of the pulse envelope. Here, we present simulations and experimental evidence that the production of high-harmonic light can be restricted to one or a few cycles on the leading edge of a laser pulse by a gating mechanism that employs time-dependent ionization of the conversion medium. This scheme enables the generation of broadband and tunable attosecond pulses. Instead of fixing the carrier-envelope phase to produce a cosine driver pulse, the phase becomes a control parameter for the center frequency of the attosecond pulse. A method to assess the multiplicity of attosecond pulses in the pulse train is also presented. The results of our study suggest an avenue towards relaxing the requirement of few-cycle pulses for isolated attosecond pulse generation.
authors: Thomas
authors: T
authors: Pfeifer
authors: Aurélie
authors: A
authors: Jullien
authors: Mark J
authors: MJ
authors: Abel
authors: Phillip M
authors: PM
authors: Nagel
authors: Lukas
authors: L
authors: Gallmann
authors: Daniel M
authors: DM
authors: Neumark
authors: Stephen R
authors: SR
authors: Leone