Phase-amplitude retrieval: SHG FROG vs. SPIDER

Summary form only given. Frequency resolved optical gating (FROG) and spectral phase interferometry for direct electric-field reconstruction (SPIDER) are nowadays leading techniques that provide access to phase-amplitude pulse retrieval. Each of these techniques has a number of outstanding features that establish the method applicability under certain experimental conditions. For instance, FROG is perfectly suited for pulse characterization precisely at the position of the sample in most spectroscopic applications because it utilizes similar excited-probe geometry. On the other hand, SPIDER has the advantage of real-time pulse measurement at high repetition rates. While in an ideal case both methods allow the precise amplitude-phase reconstruction of an ultrashort pulse, in practice specific experimental conditions such as phase-matching, detector noise etc. affect the reconstruction quality. For instance, experimental comparison of the techniques in the case characterization of a single pulse has shown some discrepancies in the retrieved parameters. We present a comparative study of SPIDER and second-harmonic generation (SHG) FROG techniques. Two main sources of errors are analyzed: the limited phase matching bandwidth of the nonlinear medium and the detector noise. We show that under similar experimental conditions SPIDER performs somewhat better than SHG FROG.