Temporal Branched Flow of Light
Abstract
Branched flow of light arises when spatially correlated disorder folds families of rays into caustics. Here, we demonstrate a temporal analog in the retarded-time coordinate of an optical pulse in a waveguide, where branched flow becomes hyper-dispersive. Retardation during pulse propagation induces spatiotemporal correlations that break propagation reciprocity and imprint a trajectory memory. This nonreciprocity enables unidirectional temporal branched flow with no spatial counterpart. A memory model is developed combining ray-density and phase fluctuations with single-ray dynamics in a memory cell. The model reveals competition between fluctuation-induced focusing and destruction, which yields nontrivial diagrams of propagation regimes with distinct dispersion scalings. For a 532-nm pulse in a LiNbO3 fiber, we predict that refractive-index disorder induced by active modulations or quantum vacuum fluctuations can produce first caustics on meter-to-kilometer scales, offering routes to experimental observation and to sensing ultra-weak fluctuations.
Related
- Hidden transverse-flow topology in partially coherent structured light
- OptoSieve: a white-light-sheet flow cytometer for simultaneous color and multispectral fluorescence phenotyping of phytoplankton
- Observation of Photon Bunching in Broadband Multimode Thermal Light Enabled by Temporal Imaging
- Observation of quadrature-dependent unidirectional flow of light
- ButterMamba: Butterworth-Enhanced Spatial-Temporal Mamba for Efficient Traffic Flow Prediction
BibTeX
@misc{ding2026temporal,
title = {{Temporal Branched Flow of Light}},
author = {Weifeng Ding and Chaokai Yang and Zhaoying Wang and Fanglin Bao},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.04232},
eprint = {2610.04232},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.04232},
}
RIS
TY - UNPB
TI - Temporal Branched Flow of Light
AU - Weifeng Ding
AU - Chaokai Yang
AU - Zhaoying Wang
AU - Fanglin Bao
PY - 2026
DA - 2026/10/03
PB - arXiv
DO - 10.48550/arxiv.2610.04232
UR - https://arxiv.org/abs/2610.04232
AB - Branched flow of light arises when spatially correlated disorder folds families of rays into caustics. Here, we demonstrate a temporal analog in the retarded-time coordinate of an optical pulse in a waveguide, where branched flow becomes hyper-dispersive. Retardation during pulse propagation induces spatiotemporal correlations that break propagation reciprocity and imprint a trajectory memory. This nonreciprocity enables unidirectional temporal branched flow with no spatial counterpart. A memory model is developed combining ray-density and phase fluctuations with single-ray dynamics in a memory cell. The model reveals competition between fluctuation-induced focusing and destruction, which yields nontrivial diagrams of propagation regimes with distinct dispersion scalings. For a 532-nm pulse in a LiNbO_3 fiber, we predict that refractive-index disorder induced by active modulations or quantum vacuum fluctuations can produce first caustics on meter-to-kilometer scales, offering routes to experimental observation and to sensing ultra-weak fluctuations.
ER -