XRM 2026 Experimental data

TIME-RESOLVED DARK-FIELD X-RAY MICROSCOPY

Revealing Defect-Mediated Lattice Dynamics with Time-Resolved Dark-Field X-ray Microscopy

Time-resolved DFXM images how a laser-induced strain field propagates and undergoes mode conversion upon interacting with defects. The high penetration depth of X-rays enables subsurface wave components to be tracked throughout the bulk.

View figures & analysis ↓ View DFXM movies ↓
Seong Gook KimPOSTECH · Max Planck POSTECH/Korea Research Initiative

EXPERIMENTAL DATA

Movies

01-1

Experimental data movie

All pump–probe delay measurements were interleaved with periodic intact-state measurements to verify reversible sample recovery and measurement reproducibility.

01-2

Annotated elastic-wave propagation

Blue arrows indicate the longitudinal strain wave propagating along the depth direction, while red arrows indicate the transverse elastic wave propagating in plane.

01-3

Larger-beam case: extended field of view

A larger beam size enables a broader sample region to be probed. Consistent longitudinal and transverse wave responses are also observed near the dislocation on the right; the red arrows specifically mark the transverse in-plane component.

01-4

Other case: weak-contrast dislocation

The same in-plane transverse strain-wave response is observed at a weak-contrast dislocation located at or very near the surface from 1,000 to 6,000 ps. The red arrow marks its propagation.

SUPPORTING ANALYSIS

Research snapshots

Swipe through the analysis—from ultrafast excitation to strain-wave propagation.

Schematic of the time-resolved dark-field X-ray microscopy experiment
01 · EXPERIMENT

Time-resolved DFXM geometry

Pump–probe geometry for imaging laser-induced lattice dynamics in bulk Ge using the (220) reflection.

Calculated electron and lattice temperatures as a function of time
02 · EXCITATION

Electronic and lattice temperature response

Two-temperature-model calculation of the ultrafast laser excitation in germanium.

Waterfall plot showing the temporal evolution of strain profiles
03 · EVOLUTION

Evolution of the laser-induced strain field

Depth-resolved profiles reveal how the strain distribution evolves across the pump–probe delay series.

Trajectory analysis of the longitudinal wave component
04 · LONGITUDINAL

Depth-direction wave propagation

Trajectory analysis tracks the longitudinal component across successive pump–probe delays.

Trajectory analysis of the in-plane transverse wave component
05 · TRANSVERSE

In-plane wave propagation

The corresponding trajectory analysis isolates the slower in-plane transverse component.