How well does the FROG algorithm perform? Very well!
While the FROG algorithm is iterative, it is also very fast, converging in a few tenths of a second for most laser pulses. It can take longer for complex pulses, or if it is written in slow code. In general, it's very reliable. Occasionally, for very complex pulses (like the one on the right), it can fail to converge, but, when it does, it's clear that you need to try again because the retrieved trace won't match the measured one.
Also, when a trace is measured by averaging over an unstable train of different pulses, disagreement will occur--this is usually why such disagreement occurs. But this is good: FROG tells you that your train of pulses is most likely unstable. Learn more about our recent work on this subject in the News section.