README

Data supporting "Photoelectron interferometry with spectrally shaped polychromatic infrared pulses"


1. GENERAL INFORMATION

Recommended citation:
https://doi.org/10.5878/8f7p-tt33

Responsible organization:
Lund University

Project registration number (diarienummer):
[Insert the verified institutional registration number, if available.]

Related publication:
E. A. Boati et al., "Photoelectron interferometry with spectrally shaped polychromatic infrared pulses".

Description:
This dataset contains experimental and numerical data supporting the study of laser-assisted photoelectron interferometry with a spectrally shaped polychromatic infrared probe. The probe consists of five narrow spectral components arranged as a Golomb ruler in the frequency domain.

The data include experimental photoelectron spectrograms, simulated spectrograms obtained using the strong-field approximation (SFA) and the time-dependent Schrodinger equation (TDSE), and a temporal profile of the simulated infrared field. They support the analysis of interference patterns and their dependence on probe intensity and ponderomotive effects.


2. ESSENTIAL INFORMATION FOR DATA REUSE

Experimental measurements:
Helium atoms were photoionized using extreme-ultraviolet (XUV) pulses in the presence of a synchronized infrared (IR) probe. The XUV pulses were generated through high-order harmonic generation in argon. A 4f pulse shaper selected five narrow spectral components of the IR probe.

Photoelectron kinetic-energy spectra were recorded using a 2m magnetic-bottle electron spectrometer while scanning the relative delay between the XUV and IR pulses. The resulting spectrograms describe the photoelectron signal as a function of kinetic energy and relative delay.

Numerical calculations:
SFA calculations were performed using the transition amplitude described in Eq. (3) of the related publication.

TDSE calculations were performed for atomic hydrogen, with the XUV photon energy adjusted to produce photoelectron energies comparable to those measured experimentally in helium.

For the simulations associated with Figures 3c and 3e, each of the five IR spectral components has an intensity of 2.00e10 W/cm^2. The intensities used for Figure 7 are listed below.

Coordinate conventions:
- Photoelectron kinetic energy is expressed in electronvolts (eV).
- Relative XUV-IR delay is expressed in femtoseconds (fs).
- In the Figure 6a file, delay_fs denotes the time coordinate of the simulated IR pulse.
- IR intensities listed in this README refer to individual spectral components, not the combined peak intensity of the polychromatic field.


3. DATASET ORGANIZATION

The files correspond to the following figure panels in the related publication. Replace the bracketed entries with the exact filenames, including relative folder paths where applicable.

Figure 3a:
helium_experimental_photoelectron_spectrogram.csv
Experimental photoelectron spectrogram.

Figure 3c:
sfa_photoelectron_spectrogram_2e10Wcm2.csv
SFA photoelectron spectrogram.

Figure 3e:
hydrogen_tdse_photoelectron_spectrogram_2e10Wcm2.csv
TDSE photoelectron spectrogram.

Figure 6a:
simulated_ir_temporal_profile.csv
Temporal profile of the simulated IR probe.

Figure 7a:
sfa_photoelectron_spectrogram_1e10Wcm2_with_A2.csv
SFA data at 1.00e10 W/cm^2 per IR component, including the A^2 term.

Figure 7b:
sfa_photoelectron_spectrogram_1e10Wcm2_without_A2.csv
SFA data at 1.00e10 W/cm^2 per IR component, excluding the A^2 term.

Figure 7c:
sfa_photoelectron_spectrogram_5e10Wcm2_with_A2.csv
SFA data at 5.00e10 W/cm^2 per IR component, including the A^2 term.

Figure 7d:
sfa_photoelectron_spectrogram_5e10Wcm2_without_A2.csv
SFA data at 5.00e10 W/cm^2 per IR component, excluding the A^2 term.

Figure 7e:
sfa_photoelectron_spectrogram_1e11Wcm2_with_A2.csv
SFA data at 1.00e11 W/cm^2 per IR component, including the A^2 term.

Figure 7f:
sfa_photoelectron_spectrogram_1e11Wcm2_without_A2.csv
SFA data at 1.00e11 W/cm^2 per IR component, excluding the A^2 term.

Here, A denotes the IR vector potential. Excluding the A^2 term means omitting the quadratic vector-potential contribution to the SFA phase while retaining the term linear in A.


4. DATAFILE DESCRIPTIONS

4.1 Experimental spectrogram: Figure 3a

The file contains three columns. Each row gives the experimental photoelectron signal at a particular delay and kinetic energy.

Column 1: delay_fs
Relative delay between the XUV and IR pulses.
Unit: fs.

Column 2: photoelectron_energy_eV
Kinetic energy of the emitted photoelectron.
Unit: eV.

Column 3:
Counts of experimental photoelectrons.


4.2 Simulated spectrograms: Figures 3c and 3e

The files contain three columns. Each row gives the calculated photoelectron signal at a particular delay and kinetic energy.

Column 1: delay_fs
Relative delay between the XUV and IR pulses.
Unit: fs.

Column 2: photoelectron_energy_eV
Final photoelectron kinetic energy.
Unit: eV.

Column 3:
Calculated photoelectron signal obtained using SFA or TDSE, as indicated by the filename mapping.


4.3 Simulated IR temporal profile: Figure 6a

The original file description identifies two columns:

Column 1: delay_fs
Time coordinate of the simulated IR pulse.
Unit: fs.

Column 2: E_IR
Envelope of the simulated IR electric field, according to the original variable description.


4.4 SFA intensity comparison: Figures 7a-7f

The original file descriptions identify three-column spectrograms with the same structure as the SFA data for Figure 3c:

Column 1: delay_fs
Relative XUV-IR delay.
Unit: fs.

Column 2: photoelectron_energy_eV
Final photoelectron kinetic energy.
Unit: eV.

Column 3:
Calculated photoelectron signal.

The intensity and inclusion or exclusion of the A^2 term for each file are listed in Section 3.


5. FILE FORMAT AND PROCESSING

File format:
csv

Data layout:
For three-column spectrogram files, the first two columns identify the delay-energy coordinates and the third column contains the corresponding signal. Use these coordinate values to reconstruct