Multiphysics simulation of all-optical switching and sequential magneto-optic readout in an integrated Si3N4/GdFeCo waveguide
Abstract
In an integrated all-optical magnetic device, a guided pulse writes a magnetic state and a later optical signal reads it out. We study both steps for an 8 nm GdFeCo film inserted across a Si3N4 waveguide. A three-dimensional dispersive finite-difference time-domain calculation gives the energy absorbed from an 800 nm pump pulse. This energy drives a four-temperature model and calibrated stochastic two-sublattice Landau-Lifshitz-Bloch dynamics. After relaxation, a separate 532 nm probe is propagated through the fixed magnetic state for the optical readout. At the reference pump fluence, the model reverses 0.859 of the film from either saturated state. The switched fraction remains within 0.81-0.87 over a 2.4-fold range of incident fluence. A threshold rule applied to the local absorption map reproduces the five three-dimensional simulation points to within 8×10−4, showing that, within the model, incomplete reversal results from non-uniform guided-mode absorption. When the film starts from zero magnetization, thermal noise orients the recovered local moments at random; over 16 realizations, 0.502 ± 0.004 of the cells end with a negative x component of the FeCo moment. Among the simulated states, the probe transmission, reflection, and absorption fractions vary by at most 0.02. The magnetic Faraday and Kerr rotations are much more sensitive and become about 12 and 130 times smaller, respectively, in the stochastically recovered state than in a saturated film. The reflected signal also contains a magnetization-independent geometric background, which can be removed by subtracting a reference signal. These results link the switching efficiency to the guided-mode absorption profile and predict polarization-based readout of the simulated magnetic states. The model assumes a homogeneous film and neglects spatial exchange stiffness and subsequent domain coarsening.
Related
- Sequential Multistep Nanoimprint Lithography Fabrication of Zero-Mode Waveguide Nanoaperture Arrays to Enhance Single-Molecule Fluorescence Detection
- Interest of Multiphysics and Multilevel Simulation Approaches to Enhance the Machining Process
- Integrated Population Balance and Multiphysics Modeling for Predicting Undesired Agglomeration in Small Molecule Manufacturing
- Comprehensive Acoustic Characterization of a Broadband Lateral MEMS Ultrasonic Transducer by Near-Field Acoustic Holography and Coupled Multiphysics Simulation
- Design, Modeling, and Characterization of High-Performance 1550-nm InGaAsP/InP Spot-Size Converter Integrated Waveguide Photodiode
BibTeX
@misc{mulyana2026multiphysics,
title = {{Multiphysics simulation of all-optical switching and sequential magneto-optic readout in an integrated Si$_3$N$_4$/GdFeCo waveguide}},
author = {Muhammad Arief Mulyana and Budi Adiperdana and Ayi Bahtiar},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.22969},
eprint = {2608.22969},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.22969},
}
RIS
TY - UNPB
TI - Multiphysics simulation of all-optical switching and sequential magneto-optic readout in an integrated Si_3N_4/GdFeCo waveguide
AU - Muhammad Arief Mulyana
AU - Budi Adiperdana
AU - Ayi Bahtiar
PY - 2026
DA - 2026/10/25
PB - arXiv
DO - 10.48550/arxiv.2608.22969
UR - https://arxiv.org/abs/2608.22969
AB - In an integrated all-optical magnetic device, a guided pulse writes a magnetic state and a later optical signal reads it out. We study both steps for an 8 nm GdFeCo film inserted across a Si_3N_4 waveguide. A three-dimensional dispersive finite-difference time-domain calculation gives the energy absorbed from an 800 nm pump pulse. This energy drives a four-temperature model and calibrated stochastic two-sublattice Landau-Lifshitz-Bloch dynamics. After relaxation, a separate 532 nm probe is propagated through the fixed magnetic state for the optical readout. At the reference pump fluence, the model reverses 0.859 of the film from either saturated state. The switched fraction remains within 0.81-0.87 over a 2.4-fold range of incident fluence. A threshold rule applied to the local absorption map reproduces the five three-dimensional simulation points to within 8×10^−4, showing that, within the model, incomplete reversal results from non-uniform guided-mode absorption. When the film starts from zero magnetization, thermal noise orients the recovered local moments at random; over 16 realizations, 0.502 ± 0.004 of the cells end with a negative x component of the FeCo moment. Among the simulated states, the probe transmission, reflection, and absorption fractions vary by at most 0.02. The magnetic Faraday and Kerr rotations are much more sensitive and become about 12 and 130 times smaller, respectively, in the stochastically recovered state than in a saturated film. The reflected signal also contains a magnetization-independent geometric background, which can be removed by subtracting a reference signal. These results link the switching efficiency to the guided-mode absorption profile and predict polarization-based readout of the simulated magnetic states. The model assumes a homogeneous film and neglects spatial exchange stiffness and subsequent domain coarsening.
ER -