Laser-free GHz stroboscopic transmission electron microscope: Components, system integration, and practical...

Area of Science:

• * Physics
• * Materials Science
• * Electron Microscopy

Background:

• * Conventional transmission electron microscopes (TEMs) typically use continuous electron beams.
• * Achieving high temporal resolution in TEMs often requires external excitation sources like lasers.
• * There is a need for TEMs capable of intrinsic time-resolved measurements for studying fast dynamic processes.

Purpose of the Study:

• * To modify a 300 keV TEM to generate broadband pulsed electron beams.
• * To achieve picosecond-level temporal resolution without an external excitation laser.
• * To enable dual-use functionality for both pulsed and continuous beam modes.

Main Methods:

• * Modification of a 300 keV TEM with a pair of phase-matched traveling wave metallic comb striplines (pulsers).
• * Installation of pulsers below the electron gun to preserve existing optical configurations.
• * Testing with an electric-field-driven pump-probe experiment.

Main Results:

• * Achieved an initial temporal resolution of 30 picoseconds (ps) at a 6.0 GHz strobe frequency.
• * Demonstrated the capability to produce pulsed beams in the 40 MHz to 12 GHz range.
• * Successfully integrated the pulsed beam capability into an in-service microscope.

Conclusions:

• * The developed modification enables intrinsic time-resolved TEM imaging with high temporal resolution.
• * The dual-use capability allows for versatile applications in both pulsed and continuous modes.
• * Future work can extend this technology for broad applicability in studying cyclical and repeatable phenomena.