HIGH-RESOLUTION PHOTOELECTRON SPECTROSCOPY BY SPECTRAL PHASE STEP MODULATION

Femtosecond-induced resonance-enhanced multi-photon ionization photoelectron spectroscopy (REMPI-PES) has the drawback of low spectral resolution due to broadband spectrum of the laser. In this paper, we theoretically demonstrate that high-resolution REMPI-PES can be achieved by shaping the femtosecond laser pulse with spectral phase step modulation. Our results show that, by manipulating the phase step position and the modulation depth, a narrowband peak or hole in the photoelectron spectrum can be observed, and the position of the narrowband peak or hole is correlated with the eigenenergy of the excite state. Therefore, both high-resolution REMPI-PES and the excited state structure can be obtained by observing the narrowband peaks or holes.