MEASUREMENT OF 10-FS LASER-PULSES

We report full characterization of the intensity and phase of similar to 10-fs optical purses using second-harmonic-generation frequency-res olved-optical-gating (SHG FROG). We summarize the subtleties in such m easurements, compare these measurements with predicted pulse shapes, a nd describe the implications of these measurements for the creation of even shorter pulses. We also discuss the problem of validating these measurements. Previous measurements of such short pulses using techniq ues such as autocorrelation have been difficult to validate because at best incomplete information is obtained and internal self-consistency checks are lacking. FROG measurements of these pulses, in contrast, c an be validated, for several reasons. First, the complete pulse-shape information provided by FROG allows significantly better comparison of experimental data with theoretical models than do measurements of the autocorrelation trace of a pulse. Second, there exist internal self-c onsistency checks in FROG that are not present in other pulse-measurem ent techniques. Indeed, we show how to correct a FROG trace with syste matic error using one of these checks.