Controlling the multi-electron dynamics in the high harmonic spectrum from N₂O molecule using TDDFT

Area of Science:

• Quantum optics
• Molecular physics
• Computational chemistry

Background:

• High harmonic generation (HHG) is a key process for creating ultrashort light pulses.
• Understanding HHG in molecules is crucial for attosecond science and molecular imaging.
• Nitrous oxide (N2O) presents a complex multi-atomic system for studying HHG dynamics.

Purpose of the Study:

• To investigate high harmonic generation in a multi-atomic nitrous oxide molecule.
• To explore the influence of multi-electron and inner orbital effects on harmonic spectra.
• To analyze the role of valence electrons in controlling HHG and extending the harmonic plateau.

Main Methods:

• Comprehensive three-dimensional time-dependent density functional theory (TD-DFT) calculations.
• Analysis of molecular dynamics and electron trajectories.
• Wavelet transform for time-frequency analysis of induced dipole acceleration.
• Investigation of chirped laser pulse effects on broadband amplitude.

Main Results:

• Explored a broad harmonic plateau in nitrous oxide.
• Analyzed the impact of multi-electron and inner orbitals on harmonic spectra and attosecond pulse generation.
• Identified valence electrons as key controllers for extending the harmonic plateau.
• Demonstrated the generation of an isolated 68 attosecond (as) pulse by optimizing laser parameters (2.5 × 10^14 W cm^-2).

Conclusions:

• TD-DFT provides accurate insights into complex HHG phenomena in multi-atomic molecules.
• Optimized laser parameters are critical for generating isolated, ultrashort attosecond pulses.
• This study advances the understanding and control of HHG for applications in ultrafast science.