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MM: Fachverband Metall- und Materialphysik

MM 52: Topical Session: In Situ and Multimodal Microscopy in Materials Physics II

MM 52.4: Talk

Thursday, March 21, 2024, 11:15–11:30, C 130

Approaching 1 ns Temporal Resolution in Time-Resolved Electron Holography by Improving Control Signals — •Simon Gaebel, Hüseyin Çelik, Tolga Wagner, Tore Niermann, and Michael Lehmann — Technische Universität Berlin, Germany

Interference Gating (iGate) is a novel and robust method for obtaining time-resolved phase information within transmission electron microscopes (TEM). Its basic idea is a time-dependent suppression of the interference pattern, realized by a deflector in the beam path to which a noise-based control signal is applied. By switching the noise on and off, an interference pattern is generated at short intervals, producing phase information from noise-free periods only.

In this presentation, a novel implementation is presented that aims to achieve increased temporal resolution approaching 1 ns due to an improved control signal. It utilizes the fact that interference patterns not only disappear in the presence of noise, but also when pi-phase shifted patterns are superimposed. The advantage of this approach is the use of square-wave-based control signals (commonly used in telecommunications), which require considerably lower amplitudes and at the same time can be hardware corrected (e.g., impedance matching).

This innovative approach makes iGate interesting for the investigation of processes at higher frequencies, as it enables the recording of phase information in the single-digit nanosecond range and opens new ways of understanding ultrafast phenomena at the nanoscale.

Keywords: Time resolved electron holography; Interference gating; Ultra-fast transmission electron microscopy