Time-frequency mapping of two-colour photoemission driven by harmonic radiation

The use of few-femtosecond, extreme ultraviolet (XUV) pulses, produced by high-order harmonic generation, in combination with few-femtosecond infrared (IR) pulses pump-probe experiments has great potential to disclose ultrafast dynamics molecules, nanostructures and solids. A crucial prerequisite is a reliable characterization the temporal properties XUV IR pulses. Several techniques have been developed. majority them applies phase reconstruction algorithms photoelectron spectrogram obtained ionizing an atomic target fashion. If radiation single harmonic, all information encoded two-color two-photon signal called sideband (SB). In this work, we present simplified model interpret time-frequency mapping SB show that dispersion directly maps onto shape its spectrogram. Finally, derive analytical solution, which allows us propose novel procedure estimate second-order real time no need for iterative algorithms.