Ultra-broadband and time-resolved depolarized dynamic light scattering for probing molecular dynamics in supercooled liquids and glasses
Abstract
Dynamic light scattering (DLS) is a versatile technique for probing microscopic dynamics in soft condensed matter. However, applying DLS to supercooled molecular liquids and glasses demands exceptional experimental performance due to weak depolarized scattering, slow relaxation near the glass transition, and the need for quantitative comparison with complementary spectroscopic techniques. In this tutorial we discuss, how a depolarized dynamic light scattering (DDLS) setup can be tailored to meet these challenges. By combining conventional fiber-optical photon correlation spectroscopy, and multispeckle photon correlation imaging with high-frequency DDLS, such a setup allows to capture rotational dynamics across more than 20 orders of magnitude in time. We detail the experimental design required for high signal-to-noise ratios and long-term optical stability, alongside the treatment of coherence and partial heterodyning effects. As we demonstrate, after proper treatment the different detection schemes yield the same electric-field autocorrelation function, enabling the construction of continuous, ultra-broadband DDLS datasets. Furthermore, multispeckle detection enables time-resolved correlation measurements without temporal averaging, extending DDLS to non-equilibrium systems such as aging molecular glasses. This methodology establishes a unified experimental framework for quantitative investigations of equilibrium and non-equilibrium molecular reorientation dynamics over an exceptionally broad time range.
Versions
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BibTeX
@misc{bohmer2026ultrabroadband,
title = {{Ultra-broadband and time-resolved depolarized dynamic light scattering for probing molecular dynamics in supercooled liquids and glasses}},
author = {Till Böhmer and Rolf Zeißler and Robin Schwäch and Jan P. Gabriel and Florian Pabst and Thomas Blochowicz},
howpublished = {arXiv},
year = {2026},
month = jul,
doi = {10.48550/arxiv.2607.25506},
eprint = {2607.25506},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.25506},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Ultra-broadband and time-resolved depolarized dynamic light scattering for probing molecular dynamics in supercooled liquids and glasses
AU - Till Böhmer
AU - Rolf Zeißler
AU - Robin Schwäch
AU - Jan P. Gabriel
AU - Florian Pabst
AU - Thomas Blochowicz
PY - 2026
DA - 2026/07/28
PB - arXiv
DO - 10.48550/arxiv.2607.25506
UR - https://arxiv.org/abs/2607.25506
AB - Dynamic light scattering (DLS) is a versatile technique for probing microscopic dynamics in soft condensed matter. However, applying DLS to supercooled molecular liquids and glasses demands exceptional experimental performance due to weak depolarized scattering, slow relaxation near the glass transition, and the need for quantitative comparison with complementary spectroscopic techniques. In this tutorial we discuss, how a depolarized dynamic light scattering (DDLS) setup can be tailored to meet these challenges. By combining conventional fiber-optical photon correlation spectroscopy, and multispeckle photon correlation imaging with high-frequency DDLS, such a setup allows to capture rotational dynamics across more than 20 orders of magnitude in time. We detail the experimental design required for high signal-to-noise ratios and long-term optical stability, alongside the treatment of coherence and partial heterodyning effects. As we demonstrate, after proper treatment the different detection schemes yield the same electric-field autocorrelation function, enabling the construction of continuous, ultra-broadband DDLS datasets. Furthermore, multispeckle detection enables time-resolved correlation measurements without temporal averaging, extending DDLS to non-equilibrium systems such as aging molecular glasses. This methodology establishes a unified experimental framework for quantitative investigations of equilibrium and non-equilibrium molecular reorientation dynamics over an exceptionally broad time range.
ER -