Momentum-resolved spectroscopy based on time-reversed light pulses emitted from optically driven quasiparticles

High harmonic generation has been observed in various crystalline solids and has recently been used to reconstruct the energy band structure of electrons in an all-optical manner. In this study, we investigate the real-time quasiparticle dynamics induced by an optical excitation pulse and a subsequent few-cycle pulse [1]. We show the appearance of echoes with the time-reversed waveform of the excitation pulse when the quasiparticle wavepackets recombine and that the frequency of the echoes reflects the dispersion relation of the quasiparticles. Furthermore, the echoes can be observed even in correlated insulators such as a Mott insulator and a charge-ordered insulator. These results provide a framework of momentum-resolved spectroscopy of quasiparticles in a wide variety of crystalline solids.