Attosecond dynamical Franz-Keldysh effect in polycrystalline diamond

Area of Science:

• Solid-state physics
• Quantum optics
• Materials science

Background:

• Intense laser pulses probe the complex interplay between classical and quantum optical responses in dielectrics.
• The precise roles of interband and intraband electronic transitions in this regime are not fully understood.

Purpose of the Study:

• To elucidate the dominant physical mechanisms governing the interaction of intense, short laser pulses with dielectrics.
• To investigate the transition regime between classical and quantum optical responses.

Main Methods:

• Attosecond transient absorption spectroscopy was employed to study polycrystalline diamond.
• Experiments utilized few-femtosecond infrared pulses below the optical breakdown threshold.
• Ab initio time-dependent density functional theory (TDDFT) calculations were performed.

Main Results:

• Experimental results were successfully explained using TDDFT and a two-band parabolic model.
• The dynamical Franz-Keldysh effect was identified as a key theoretical framework.
• Infrared pulse-induced intraband currents were identified as the primary mechanism.

Conclusions:

• Intraband currents, driven by infrared pulses, are the dominant factor in the observed optical responses.
• This work clarifies the fundamental physics of light-matter interactions in dielectrics under intense fields.