Generation of Sub-900- $\mu$J Supercontinuum With a Two-Octave Bandwidth Based on Induced Phase Modulation in Argon-Filled Hollow Fiber

We succeeded in generating 860-
$\mu$
J pulses spanning the range from 270 to 1000 nm, the highest energy two-octave pulses demonstrated to date, by utilizing not only self-phase modulation but also induced phase modulation based on nonlinear copropagation of fundamental and second-harmonic femtosecond pulses in a pressure gradient Ar-gas-filled hollow fiber. This corresponds to 1.5-fs 0.3-TW 0.65-cycle transform-limited pulses at a 1-kHz repetition rate, which serves as an optical source for ultrafast ultra-broadband spectroscopy and quantum control as well as attosecond science and technology.