Recent progress toward real-time measurement of ultrashort laserpulses

摘要

Frequency-resolved optical gating (FROG) is a technique thatnproduces a spectrogram of an ultrashort laser pulse optically. While angreat deal of information about the pulse can be gleaned from its FROGntrace, often it is desirable to obtain of the pulse informationnimmediately, in real time. Quantitative information about the guise isnnot readily obtainable from its spectrogram without the use of antwo-dimensional phase retrieval algorithm. While current algorithms arenquite robust, retrieval of all the pulse information can be slow. Innthis paper, I describe a recently developed FROG trace inversionnalgorithm called Principal Component Generalized Projects that is fast,nrobust, and can invert FROG traces in real time. A femtosecondnoscilloscope based on second-harmonic generation FROG is also describednthat uses this new algorithm to rapidly (up to 2.3 Hz) and continuouslyndisplay the intensity and phase of ultrashort laser pulses