Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 32: Nanomechanical systems (joint session HL/TT)
TT 32.10: Talk
Tuesday, March 10, 2026, 12:30–12:45, POT/0051
Nonlinear vibrational dynamics locally probed by time-resolved electron diffraction — •Kai Nettersheim1, Alexander Schröder1, and Sascha Schäfer1,2 — 1Department of Physics, University of Regensburg, Regensburg, Germany — 2Regensburg Center for Ultrafast Nanoscopy (RUN), Regensburg, Germany
Nonlinear dynamics of micro- and nanoscale electro-mechanical systems can be observed using electrical or optical methods. However, these approaches are often limited in their spatial resolution, which leaves the underlying mechanics only partially accessible. Recent advances in ultrafast electron microscopy (UTEM) enable the highly localized probing of nanoscale oscillators, allowing to retrieve detailed information about their atomic structure and material defects.
Utilizing stroboscopic UTEM imaging techniques, we present the characterization of nonlinear mode dynamics in free-standing silicon membranes employing an event-based electron detector with nanosecond temporal resolution [1]. The high-Q resonator is excited using an optical pulse train driving the sample into the nonlinear regime. Due to the use of event-based converged electron beam diffraction (CBED), phase-accurate measurements of the nanoscale structural motion are provided. Whereas at weak driving, the oscillator displays a simple Duffing-type bistability, higher harmonic overtones as well as period doubling dynamics emerge at higher driving amplitudes.
[1] A. Schröder et al., Ultramicroscopy 256, 113881 (2024)
Keywords: UTEM; MEMS; Nonlinear Dynamics; Duffing Oscillator