(color online) Total output-pulse intensity profiles in panels (a), (c), (e) time and panels (b), (d), (f) frequency domains for pulses with different initial energies passing through 1-m-long argon gas-filled HCFs at different gas pressure: (a) and (b) 0.3-, 0.4-, and 0.5-mJ input pulses at 250 mbar; (c) and (d) 0.1-, 0.2-, and 0.3-mJ input pulses at 500 mbar; and (e), (f) 0.05-, 0.1-, and 0.15-mJ input pulses at 1 bar.