Measuring ultrashort pulses in the single-cycle regime:Frequency-resolved optical gating

In this chapter, we developed the theory of frequency-resolved optical gating (FROG) in the few-cycle regime and applied it to the SHC FROG measurement of 2.5-optical-cycle pulses with a central wavelength around 800 nm. These are some of the shortest pulses that have been completely characterized to date. We also describe the measurement of uncompressed strongly nontransform-limited weak-intensity continuum pulses. These two key measurements, which are required to design, test, and optimize the pulse compressor, were both performed without a single change in the SHG FROG apparatus. No other pulse measurement technique known allows such simplicity and versatility.