Octave-spanning supercontinuum coherent soft x-ray for producing a single-cycle soft x-ray pulse.

This study demonstrates the potential to generate a soft x-ray single-cycle attosecond pulse using a single-cycle mid-infrared pulse from advanced dual-chirped optical parametric amplification (DC-OPA). A super continuum high harmonic (HH) spectrum was generated in argon (80-160 eV) and neon (150-270 eV). The experimental spectra reasonably agree with those calculated by the strong-field approximation model and Maxwell's equations.