a) Single-pulse spectrum (lightblue-solid), the filtered single-pulse spectrum (lightblue-dotted), the burst spectrum (darkblue-solid), and the filtered burst spectrum (orange-filled). (b)–(d) Measured energy (top) and spectra (bottom) dependent on the phase-slip offset in burst-mode (10 pulses) at 0.52 ps intraburst pulse spacing. (b) Without spectral filtering. (c), (d) With spectral filtering (c) after and (d) prior to amplification. For validation, the spectral sum $\sum _{i}S({\mathrm{\Phi }}_{s,m},{\lambda }_i)\Delta \lambda$ at each corresponding phase slip Φ_s,m (blue line) is compared with the energies acquired from the powermeter (purple-dashed line). For the spectrally filtered cases, the filtered single-pulse spectrum is also included.