SIMBA: A new technique for ultrashort pulse characterization

A novel technique (spectral interferometry using minimum-phase based algorithm, or SIMBA) to recover the phase and magnitude of the electric-field profile of weak ultra-short laser pulses is presented. SIMBA involves measuring with an optical spectrum analyzer (OSA) the power spectrum of a sequence consisting of a dummy pulse followed by the sample pulse to be characterized. The sample pulse profile is then uniquely retrieved either with the analytical Hubert transformation or with a simple iterative error-reduction algorithm applied to this spectrum. SIMBA presents several significant advantages over existing techniques: it does not require a reference pulse with a known profile, which reduces measurement time and complexity significantly; the experimental set-up is simple and has no moving parts; data processing is fast, allows real-time characterization, and exhibits a lower sensitivity to measurement noise; it can be used to characterize ultraweak pulses; it discriminates between a pulse and its time reversal; and it can characterize a series of multiple pulses with a single OSA measurement.