GRENOUILLE and FROG

FROG (frequency-resolved optical gating) has many geometries. Especially, we can categorize the FROG geometries into two types according to how to take the spectra: a single-shot geometry and a multi-shot geometry. In general, a single-shot geometry is simpler than a multi-shot geometry because a single-shot geometry does not use a motorized variable moving stage to change the delay between pulses. The single-shot FROG geometry, however, still requires splitting a beam and recombining the two beams in time and space.

GRENOUILLE, a simplified version of a single-shot SHG FROG, has only a few optical elements that split a beam and recombine the replicas automatically. In addition, a thick crystal acts like a grating, so it can be used for obtaining a spectrally resolved trace, that is, a FROG trace. The table below summarizes the features of GRENOUILLE and SHG FROG.