Sub femto-joule sensitive single-shot XFROG measurements based on optical parametric amplification

A new single-shot XFROG technique for characterizing ultrashort optical pulses with extremely weak intensity is demonstrated. The design uses beam-crossing OPA-FROG with all-reflective optics which enables the measurement of optical pulse with pulse energy less than femto-joule and pulse width as short as a few femtoseconds. The measurable wavelength range from visible to IR, depending on the phase-matching of the nonlinear crystal used, the pump wavelength and the configuration of OPA.