Chinese Physics Letters

Manipulation of Resonance-Enhanced Multiphoton-Ionization Photoelectron Spectroscopy by Two Time-Delayed Femtosecond Laser Pulses

Chenhui Lu, Shian Zhang, Zhen-Rong Sun

Published Nov 1, 2013• 2 citations

Abstract

We theoretically demonstrate that the (2+1) resonance-enhanced multiphoton-ionization (REMPI) photoelectron spectrum in a cesium (Cs) atom can be effectively manipulated by two time-delayed femtosecond laser pulses, involving its photoelectron spectral structure and photoelectron energy. We show that the photoelectron spectrum exhibits interference fringes and the fringe spacing is determined by the time delay of the two laser pulses, and the photoelectron energy is periodically modulated and the modulation period is determined by the two-photon transition frequency of the excited state. Finally, we utilize the power spectrum of the two time-delayed laser pulses and the two-photon transition probability of the excited state to respectively explain the modulations of the photoelectron spectrum and photoelectron energy.

DOI: 10.1088/0256-307x/30/11/113302

Related papers

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

Shian Zhang, Chenhui Lu, Tianqing Jia +2 more

The Journal of Chemical PhysicsNov 2, 201212 citations

Bichromatic phase control of interfering Autler-Townes spectra

Tim Bayer, Kevin Eickhoff, D. Köhnke +1 more

arXiv:2311.08248Physical Review AMar 15, 20245 citations

Photoelectron angular distributions from multiphoton ionization of cesium atoms

R. N. Compton, John A. D. Stockdale, C. Dewey Cooper +2 more

Physical Review AOct 1, 198437 citations

Coherence in multistate resonance-enhanced four-photon ionization of lithium atoms

Michael Schuricke, Klaus Bartschat, Alexei N. Grum-Grzhimailo +5 more

Physical Review AAug 30, 201315 citations

Femtosecond time-resolved spectroscopy and coherent control in Cs2

Valérie Blanchet, M. A. Bouchène, B. Girard

AIP conference proceedingsJan 1, 19960 citations

Determination of atomic multiphoton-ionization phases by trichromatic multichannel wave-packet interferometry

Kevin Eickhoff, D. Köhnke, Lea Feld +2 more

arXiv:2203.00323Physical Review AMay 16, 20229 citations

Chinese Physics Letters

Manipulation of Resonance-Enhanced Multiphoton-Ionization Photoelectron Spectroscopy by Two Time-Delayed Femtosecond Laser Pulses

Chenhui Lu, Shian Zhang, Zhen-Rong Sun

Published Nov 1, 2013• 2 citations

Publisher

Abstract

DOI: 10.1088/0256-307x/30/11/113302

Related papers

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

Shian Zhang, Chenhui Lu, Tianqing Jia +2 more

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.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.

The Journal of Chemical PhysicsNov 2, 201212 citations

Bichromatic phase control of interfering Autler-Townes spectra

Tim Bayer, Kevin Eickhoff, D. Köhnke +1 more

We propose a scheme to control the shape of the Autler-Townes (AT) doublet in the photoelectron spectrum from atomic resonance-enhanced multiphoton ionization (REMPI). The scheme is based on the interference of two AT doublets created by ionization of the strongly driven atom from the ground and the resonantly excited state using tailored bichromatic femtosecond laser pulses. In this scheme, the quantum phase of the photoelectrons is crucial for the manipulation of the AT doublet. The laser polarization state and the relative optical phase between the two colors are used to manipulate the interference pattern. We develop an analytical model to describe the bichromatic REMPI process and provide a physical picture of the control mechanism. To validate the model, the results are compared to an ab initio calculation based on the solution of the two-dimensional time-dependent Schr\"odinger equation for the nonperturbative interaction of an atom with intense polarization-shaped bichromatic femtosecond-laser pulses. Our results indicate that the control mechanism is robust with respect to the laser intensity, facilitating its experimental observation.We propose a scheme to control the shape of the Autler-Townes (AT) doublet in the photoelectron spectrum from atomic resonance-enhanced multiphoton ionization (REMPI). The scheme is based on the interference of two AT doublets created by ionization of the strongly driven atom from the ground and the resonantly excited state using tailored bichromatic femtosecond laser pulses. In this scheme, the quantum phase of the photoelectrons is crucial for the manipulation of the AT doublet. The laser polarization state and the relative optical phase between the two colors are used to manipulate the interference pattern. We develop an analytical model to describe the bichromatic REMPI process and provide a physical picture of the control mechanism. To validate the model, the results are compared to an ab initio calculation based on the solution of the two-dimensional time-dependent Schr\"odinger equation for the nonperturbative interaction of an atom with intense polarization-shaped bichromatic femtosecond-laser pulses. Our results indicate that the control mechanism is robust with respect to the laser intensity, facilitating its experimental observation.

arXiv:2311.08248Physical Review AMar 15, 20245 citations

Photoelectron angular distributions from multiphoton ionization of cesium atoms

R. N. Compton, John A. D. Stockdale, C. Dewey Cooper +2 more

We present both experimental and theoretical studies of resonantly enhanced multiphoton ionization of cesium atoms. Photoelectron angular distributions for two-photon ionization via the one-photon-allowed $7p^{2}P_{\frac{1}{2},\frac{3}{2}}$ and $8p^{2}P_{\frac{1}{2},\frac{3}{2}}$ intermediate states and three-photon ionization via the two-photon-allowed $8d^{2}D_{\frac{5}{2},\frac{3}{2}}$ resonant intermediate states are reported. The photoelectrons are energy analyzed with a spherical-sector electrostatic energy analyzer with an energy resolution of ~ 0.1 eV and angular resolution of ~ \ifmmode\pm\else\textpm\fi{}2\ifmmode^\circ\else\textdegree\fi{}. A straightforward calculation based upon a finestructure scheme gives excellent agreement with the measured angular distributions for the $^{2}P_{\frac{1}{2}}$ states. The laser pulse duration is comparable to the hyperfine precession period which allows the hyperfine coupling to partially destroy the anisotropy initially produced in the $^{2}P_{\frac{3}{2}}$ resonant intermediate states. Quantitative calculations including hyperfine coupling take this into account and provide an expression which gives a reasonable fit to the $^{2}P_{\frac{3}{2}}$ data.We present both experimental and theoretical studies of resonantly enhanced multiphoton ionization of cesium atoms. Photoelectron angular distributions for two-photon ionization via the one-photon-allowed $7p^{2}P_{\frac{1}{2},\frac{3}{2}}$ and $8p^{2}P_{\frac{1}{2},\frac{3}{2}}$ intermediate states and three-photon ionization via the two-photon-allowed $8d^{2}D_{\frac{5}{2},\frac{3}{2}}$ resonant intermediate states are reported. The photoelectrons are energy analyzed with a spherical-sector electrostatic energy analyzer with an energy resolution of ~ 0.1 eV and angular resolution of ~ \ifmmode\pm\else\textpm\fi{}2\ifmmode^\circ\else\textdegree\fi{}. A straightforward calculation based upon a finestructure scheme gives excellent agreement with the measured angular distributions for the $^{2}P_{\frac{1}{2}}$ states. The laser pulse duration is comparable to the hyperfine precession period which allows the hyperfine coupling to partially destroy the anisotropy initially produced in the $^{2}P_{\frac{3}{2}}$ resonant intermediate states. Quantitative calculations including hyperfine coupling take this into account and provide an expression which gives a reasonable fit to the $^{2}P_{\frac{3}{2}}$ data.

Physical Review AOct 1, 198437 citations

Coherence in multistate resonance-enhanced four-photon ionization of lithium atoms

Michael Schuricke, Klaus Bartschat, Alexei N. Grum-Grzhimailo +5 more

A joint experimental and theoretical study of four-photon ionization of Li is performed using a pump-probe setup with the laser frequency tuned in between the excitation energies of the $2s$ -- $4p$ and $2s$ -- $4f$ three-photon transitions. The three-dimensional photoelectron momentum pattern is recorded as a function of the delay time between two otherwise identical laser pulses. The process is modeled by numerically solving the time-dependent Schr\"odinger equation. While complicated interference patterns arise in the electron spectrum when the two pulses partially overlap in time, the expected quantum-beat phenomenon between Li atoms in either the $4p$ or the $4f$ state are seen when the fast oscillations involving the $2s$ initial state are averaged over. The qualitative agreement between the predicted and observed beating patterns is very good.A joint experimental and theoretical study of four-photon ionization of Li is performed using a pump-probe setup with the laser frequency tuned in between the excitation energies of the $2s$--$4p$ and $2s$--$4f$ three-photon transitions. The three-dimensional photoelectron momentum pattern is recorded as a function of the delay time between two otherwise identical laser pulses. The process is modeled by numerically solving the time-dependent Schr\"odinger equation. While complicated interference patterns arise in the electron spectrum when the two pulses partially overlap in time, the expected quantum-beat phenomenon between Li atoms in either the $4p$ or the $4f$ state are seen when the fast oscillations involving the $2s$ initial state are averaged over. The qualitative agreement between the predicted and observed beating patterns is very good.

Physical Review AAug 30, 201315 citations

Femtosecond time-resolved spectroscopy and coherent control in Cs2

Valérie Blanchet, M. A. Bouchène, B. Girard

We show how two identical laser pulses (with a controlled delay time) can be used to create a coherent superposition of two vibrational wave packets in a bound electronic state, which exhibit the following features as a function of the delay time between the laser pulses: high frequency oscillation (at the Bohr frequency) modulated by a slow envelope corresponding to the vibrational recurrences. We present a theoretical treatment of this effect and experimental results obtained in Cs2, with 160 fs, 768 nm laser pulses, in which the high frequency modulation is resolved, with a beat period of 2.6 fs1. Finally, we show how the detection scheme can affect the observability of these interferences when only two laser pulses are used: at 758 nm the interference fringes cannot be observed.We show how two identical laser pulses (with a controlled delay time) can be used to create a coherent superposition of two vibrational wave packets in a bound electronic state, which exhibit the following features as a function of the delay time between the laser pulses: high frequency oscillation (at the Bohr frequency) modulated by a slow envelope corresponding to the vibrational recurrences. We present a theoretical treatment of this effect and experimental results obtained in Cs2, with 160 fs, 768 nm laser pulses, in which the high frequency modulation is resolved, with a beat period of 2.6 fs1. Finally, we show how the detection scheme can affect the observability of these interferences when only two laser pulses are used: at 758 nm the interference fringes cannot be observed.

AIP conference proceedingsJan 1, 19960 citations

Determination of atomic multiphoton-ionization phases by trichromatic multichannel wave-packet interferometry

Kevin Eickhoff, D. Köhnke, Lea Feld +2 more

We present the unambiguous determination of quantum phases in the multiphoton ionization (MPI) of potassium atoms by using a multichannel photoelectron interferometry scheme based on trichromatic pulse shaping. The colors of the laser field are chosen to produce three energetically separated photoelectron interferograms in the continuum. While the red pulse is two-photon resonant with the $3d$ state resulting in a $(2+1)$ resonance-enhanced MPI (REMPI), a $(1+2)$ REMPI occurs via the nonresonant intermediate $4p$ state with an initial green or blue pulse. We show that ionization via a nonresonant intermediate state lifts the degeneracy of photoelectron interferograms from pathways consisting of permutations of the colors. The analysis of the interferograms reveals a phase shift of $\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}/2$ depending on the sign of the detunings in the $(1+2)$ REMPI pathways. In addition, we demonstrate that the photoionization time delay in the resonant $(2+1)$ REMPI pathway gives rise to a linear spectral phase in the photoelectron spectra. Insights into the underlying MPI processes are gained through an analytic perturbative description and numerical simulations of a trichromatic driven three-level system coupled to the continuum.We present the unambiguous determination of quantum phases in the multiphoton ionization (MPI) of potassium atoms by using a multichannel photoelectron interferometry scheme based on trichromatic pulse shaping. The colors of the laser field are chosen to produce three energetically separated photoelectron interferograms in the continuum. While the red pulse is two-photon resonant with the $3d$ state resulting in a $(2+1)$ resonance-enhanced MPI (REMPI), a $(1+2)$ REMPI occurs via the nonresonant intermediate $4p$ state with an initial green or blue pulse. We show that ionization via a nonresonant intermediate state lifts the degeneracy of photoelectron interferograms from pathways consisting of permutations of the colors. The analysis of the interferograms reveals a phase shift of $\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}/2$ depending on the sign of the detunings in the $(1+2)$ REMPI pathways. In addition, we demonstrate that the photoionization time delay in the resonant $(2+1)$ REMPI pathway gives rise to a linear spectral phase in the photoelectron spectra. Insights into the underlying MPI processes are gained through an analytic perturbative description and numerical simulations of a trichromatic driven three-level system coupled to the continuum.

arXiv:2203.00323Physical Review AMay 16, 20229 citations

7p^{2}P_{\frac{1}{2},\frac{3}{2}}

and

8p^{2}P_{\frac{1}{2},\frac{3}{2}}

intermediate states and three-photon ionization via the two-photon-allowed

8d^{2}D_{\frac{5}{2},\frac{3}{2}}

resonant intermediate states are reported. The photoelectrons are energy analyzed with a spherical-sector electrostatic energy analyzer with an energy resolution of ~ 0.1 eV and angular resolution of ~ \ifmmode\pm\else\textpm\fi{}2\ifmmode^\circ\else\textdegree\fi{}. A straightforward calculation based upon a finestructure scheme gives excellent agreement with the measured angular distributions for the

^{2}P_{\frac{1}{2}}

states. The laser pulse duration is comparable to the hyperfine precession period which allows the hyperfine coupling to partially destroy the anisotropy initially produced in the

^{2}P_{\frac{3}{2}}

resonant intermediate states. Quantitative calculations including hyperfine coupling take this into account and provide an expression which gives a reasonable fit to the

^{2}P_{\frac{3}{2}}

data.

A joint experimental and theoretical study of four-photon ionization of Li is performed using a pump-probe setup with the laser frequency tuned in between the excitation energies of the

2s

4p

and

2s

4f

three-photon transitions. The three-dimensional photoelectron momentum pattern is recorded as a function of the delay time between two otherwise identical laser pulses. The process is modeled by numerically solving the time-dependent Schr\"odinger equation. While complicated interference patterns arise in the electron spectrum when the two pulses partially overlap in time, the expected quantum-beat phenomenon between Li atoms in either the

4p

or the

4f

state are seen when the fast oscillations involving the

2s

initial state are averaged over. The qualitative agreement between the predicted and observed beating patterns is very good.

3d

state resulting in a

(2+1)

resonance-enhanced MPI (REMPI), a

(1+2)

REMPI occurs via the nonresonant intermediate

4p

state with an initial green or blue pulse. We show that ionization via a nonresonant intermediate state lifts the degeneracy of photoelectron interferograms from pathways consisting of permutations of the colors. The analysis of the interferograms reveals a phase shift of $\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}/2$ depending on the sign of the detunings in the

(1+2)

REMPI pathways. In addition, we demonstrate that the photoionization time delay in the resonant

(2+1)

REMPI pathway gives rise to a linear spectral phase in the photoelectron spectra. Insights into the underlying MPI processes are gained through an analytic perturbative description and numerical simulations of a trichromatic driven three-level system coupled to the continuum.