Effect of laser spectral bandwidth on coherent control of resonance-enhanced multiphoton-ionization photoelectron spectroscopy

Abstract

The high-resolution (2 + 1) resonance-enhanced multiphoton-ionization photoelectron spectroscopy (REMPI-PS) can be obtained by measuring the photoelectron intensity at a given kinetic energy and scanning the single π phase step position. In this paper, we further demonstrate that the high-resolution (2 + 1) REMPI-PS cannot be achieved at any measured position of the kinetic energy by this measurement method, which is affected by the laser spectral bandwidth. We propose a double π phase step modulation to eliminate the effect of the laser spectral bandwidth, and show the advantage of the double π phase step modulation on achieving the high-resolution (2 + 1) REMPI-PS by considering the contributions involving on- and near-resonant three-photon excitation pathways.

Stimulated Emission Enhancement Using Shaped Pulses

“…Here we explore stimulated emission resulting from the third-order polarization of cyanine dye molecules in solution when using a spectral phase step function. Two-photon transition control has been particularly successful when using a phase step because of constructive interference occurring at twice the frequency corresponding to the position of the phase step; this control has been reported for atoms as well as large organic molecules. − The similarity between two-photon excitation and coherent anti-Stokes Raman scattering (CARS) led to a phase step being used to enhance CARS signals. , Under direct resonance with a transition, a phase step has been used on isolated atoms and diatomics, detecting the resonant features as the phase step is scanned within the bandwidth of the excitation pulse. ,− There is only one case when the transmitted laser and resulting third-order polarization has been analyzed theoretically when using a phase step, and that study was inspired by the results being presented here.…”