A wide, weak component surrounding the main pulse in time, caused by uncompensated higher-order dispersion, spectral clipping, ASE or prepulses from the amplifier. It shows as wings on an autocorrelation trace. Pedestal energy does nothing useful and, in high-intensity experiments, can heat or ionize a target before the main pulse arrives, so contrast ratio is a key spec.
There's a pedestal on the autocorrelation out to 2 ps, the third-order dispersion isn't compensated.
Related terms
Autocorrelator
An instrument that measures ultrashort pulse duration by overlapping a pulse with a delayed copy of itself.
Chirp
A change in instantaneous frequency across a pulse, so its colors arrive spread out in time.
CPA
Chirped Pulse Amplification: stretching a short pulse before amplifying it, then recompressing it afterwards.
ASE
Amplified Spontaneous Emission: random spontaneous photons amplified in a gain medium, a broadband noise background.