Related Experiment Video
Updated: Jan 16, 2026
10:40
High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
7.9K
Picosecond Expansion in LaAlO_{3} Resonantly Driven by Infrared-Active Phonons.
Jakob Gollwitzer1, Jeffrey Z Kaaret2, Y Eren Suyolcu1
1Cornell University, Department of Materials Science and Engineering, Ithaca, New York 14853, USA.
Physical Review Letters
|September 26, 2025
Summary
We uncovered how laser pulses drive ultrafast structural changes in LaAlO3 thin films. This research reveals a new mechanism involving phonon-strain coupling and THz excitation
Area of Science:
- Condensed Matter Physics
- Materials Science
- Ultrafast Spectroscopy
Background:
- LaAlO3 thin films are crucial in oxide electronics.
- Understanding their response to external stimuli is key for device applications.
- Ultrafast laser excitation offers a pathway to probe and control material properties.
Purpose of the Study:
- To investigate the ultrafast structural dynamics of LaAlO3 thin films.
- To identify the underlying mechanisms of THz-driven structural changes.
- To explore the potential of THz excitation for enhancing material crystallinity.
Main Methods:
- Time-resolved X-ray diffraction and diffuse scattering.
- Optical birefringence measurements.
- First-principles theory and spring-mass modeling.
Main Results:
- Observed immediate lattice expansion and acoustic breathing modes.
- Identified direct coupling between infrared-active phonons and strain.
- Demonstrated linear scaling of acoustic mode amplitude with pump fluence.
- Showed THz excitation enhances crystallinity via nonthermal symmetry increase.
Conclusions:
- Coherent phonon-strain coupling drives ultrafast structural dynamics in LaAlO3.
- THz excitation can controllably modify lattice dynamics and enhance crystallinity.
- A multimodal approach is effective for studying nanoscale material dynamics.
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