Tracing attosecond electron emission from a nanometric metal tip

Area of Science:

• Quantum mechanics
• Solid-state physics
• Attosecond science

Background:

• Solids emit electrons via quantum tunnelling under intense electric fields, crucial for applications like electron sources and petahertz electronics.
• While attosecond electron dynamics in gases are well-characterized, measuring this in solids remains a challenge.
• Understanding subcycle electron dynamics is key to advancing strong-field physics in condensed matter.

Purpose of the Study:

• To measure the suboptical-cycle strong-field electron emission dynamics from nanostructures with attosecond precision.
• To uncover the emission time window of electrons tunnelling from solids under intense laser fields.
• To enable precise active control of strong-field photoemission from solid-state systems.

Main Methods:

• Utilized two-colour modulation spectroscopy of backscattering electrons.
• Measured photoelectron spectra from a sharp metallic tip as a function of the relative phase between two laser colours.
• Employed the time-dependent Schrödinger equation and classical trajectories to interpret phase-dependent spectral signatures.

Main Results:

• Successfully uncovered suboptical-cycle strong-field emission dynamics from nanostructures with attosecond precision.
• Determined an electron emission duration of 710 ± 30 attoseconds by matching experimental data to a quantum model.
• Established a link between spectral phase dependencies and electron emission dynamics.

Conclusions:

• The study demonstrates the capability to measure and control attosecond electron emission dynamics in solids.
• Opens new avenues for quantitative timing and active control of strong-field photoemission.
• Has direct ramifications for ultrafast electron sources, quantum degeneracy studies, and petahertz electronics.