Control of resonance enhanced multi-photon ionization photoelectron spectroscopy by phase-shaped femtosecond laser pulse

Abstract

In this paper, we theoretically demonstrate that the (2+1+1) resonance enhanced multi-photon ionization photoelectron spectroscopy in sodium atom can be effectively controlled by shaping femtosecond laser pulse with a π phase step modulation in weak laser field, involving its total photoelectron energy, maximal photoelectron intensity, and spectroscopic bandwidth. Our results show that the total photoelectron energy can be suppressed but not enhanced, the maximal photoelectron intensity can be enhanced and also suppressed, and the photoelectron spectroscopy can be tremendously narrowed. These theoretical results can provide a feasible scheme to achieve the high-resolution photoelectron spectroscopy and study the excited state structure in atomic and molecular systems.

Multidimensional spectroscopy with a single broadband phase-shaped laser pulse

“…Recent applications of phase control phase in one-dimensional spectroscopy have been reported. The spectral phase has been used to suppress processes such as two-photon absorption (TPA), by utilizing an asymmetric phase function [14,[17][18][19][20] with respect to the TPA transition frequency. Shaped-pulses have been employed in Raman spectroscopy [13,18].…”

Quantum control of femtosecond resonance-enhanced multiphoton-ionization photoelectron spectroscopy

“…We theoretically propose a π or cubic phase modulation to realize the enhancement and narrowing of REMPI-PS [26][27][28][29]. In theory, the photoelectron spectral modulation was explained by the selective population of dressed states [21][22][23][24], or multiphoton power spectrum [28,29].…”

“…Recently, the advent of the femtosecond pulse shaping technique by modulating the laser spectral phase and/or amplitude in the frequency domain opened an opportunity to effectively control the femtosecond REMPI-PS. Various phase modulation schemes have been proposed to enhance or narrow the REMPI-PS [21][22][23][24][25][26][27][28][29], and some schemes have been experimentally realized [21][22][23][24][25]. For example, Wollenhaupt et al experimentally demonstrated the selective excitation of the slow and fast photoelectron components of REMPI-PS by sinusoidal, chirped, or phase-step modulation [21-24].…”

“…We theoretically propose a π or cubic phase modulation to realize the enhancement and narrowing of REMPI-PS [26][27][28][29]. In theory, the photoelectron spectral modulation was explained by the selective population of dressed states [21][22][23][24], or multiphoton power spectrum [28,29].In our previous works [26][27][28][29], the REMPI-PS was calculated by considering the laser field in time domain; thus the physical control mechanism of the photoelectron spectral modulation cannot be directly explained from this theoretical model, which greatly limits the understanding of the resonance-enhanced multiphoton-ionization process. However, in this paper we develop a theoretical model by considering the laser field in frequency domain and show that the REMPI process involves the on-and near-resonant excitation pathways, and therefore the photoelectron spectral modulation can be well explained by the inter-and intragroup interference involving these on-and near-resonant excitation pathways.…”

Resonance-enhanced multiphoton-ionization photoelectron spectroscopy by a rectangular amplitude modulation

“…The femtosecond laser pulse is an excellent tool to create the REMPI photoelectron spectroscopy because of its broad laser spectrum and high pulse intensity, while a main drawback for the femtosecondinduced REMPI photoelectron spectroscopy is low spectral resolution due to the broadband photoelectron spectrum. Recently, various methods by the femtosecond pulse shaping technique were proposed to narrow the REMPI photoelectron spectrum [19][20][21][22][23][24][25][26][27]. For example, Wollenhaupt et al showed that the REMPI photoelectron spectrum in potassium (K) atom can be narrowed by the selective excitation of the slow and fast photoelectrons using a sinusoidal, chirped, or * sazhang@phy.ecnu.edu.cn † zrsun@phy.ecnu.edu.cn phase-step modulation [19][20][21][22][23].…”