High-speed 'multi-grid' pulse-retrieval algorithm for frequency resolved optical gating

摘要

We implemented a "multi-grid" scheme in frequency-resolved optical gating's (FROG's) generalized projections algorithm to boost pulse-retrieval speed for complex pulses. The multi-grid algorithm uses a set of coarser arrays, created from the original fine array, to provide an initial guess for an efficient retrieval from the much larger fine trace. Multi-grid is most needed by pulses with complex temporal profiles, which are best measured by cross-correlation FROG (XFROG) techniques. Applying multi-grid to XFROG, we reduced the retrieval time for complex pulses with TBP_(rms) of 40 to 90 from their XFROG traces by factors of 7-10 for pulses.