MesaPhotonics VideoFROG FROGscan, User Manual

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Chapter 7. Retrieving Pulses
09/07/2018 Vs 003 FROGSCAN USER’S MANUAL Page 53
To determine if the measurements are good, two different checks can be useful.
1. Check the FROG Trace error, although this can sometimes be misleading.
Typically, the FROG Trace error should be below about 1-2% for small grids and less than 1% for
larger grid sizes; however, if the trace is complex, the FROG Trace error might be larger than normal.
Even FROG Trace errors as large as 4-5% on a 64 x 64 grid can be acceptable. However, in this
case, another check should be performed to determine retrieval quality.
2. Another check for retrieval quality is to compare the measured FROG Trace (The FROG Trace fed
into the algorithm) with the retrieved FROG Trace (The FROG Trace that is constructed from the
retrieved pulse). The traces should be very close in general shape AND fine structure.
If the two traces are generally close, the major features of the retrieved pulse are very likely correct.
To have an excellent retrieval, the measured and retrieved FROG Traces must be very nearly exact.