AI 中文总结
本文针对集成Si₃N₄/GdFeCo波导元件，建立全光开关与磁光读出的自洽模型，揭示导波光的磁化相关特征及切换效率，为相关器件设计提供理论支撑
AI 中文摘要
尽管已有研究在氮化硅波导上实现了全光开关并完成了电学读出，但尚未计算经过全光开关后的磁膜所携带的导波光的相关特性。本文针对集成Si₃N₄/GdFeCo元件（60 μm波导上的8 nm薄膜），打通了全链条的建模：将三维色散时域有限差分求解器与吸收的光功、四温度模型、带有涨落耗散一致朗之万场的随机双亚晶格朗道-利夫希茨-布洛赫动力学耦合，磁化强度会反馈到旋电介电常数中，供第二个导波光脉冲进行读出。透射、反射和吸收对磁化强度不敏感，在饱和、退磁和多畴薄膜之间，数值接近0.974-0.975，偏移量最多为0.02，因为磁化强度仅通过反对称项进入介电张量，而吸收功率对该反对称项的依赖为二阶；磁化奇数阶偏振测量通过法拉第旋转（区分度为一个数量级）和克尔效应（区分度为两个数量级）将这些状态分开。导波几何结构带来了自由空间测量不存在的代价：反射通道存在-11.77°的几何基底，超过了其掩盖的8.24°旋转角，以退磁薄膜为参考可将其修正至0.063°。透射模式在其瓣平衡中携带了第二个特征，无需偏振测量。校准脉冲在2.4倍的注量窗口内可将薄膜从任一饱和态的0.859部分翻转，与1的差值源于光子而非磁性因素：翻转分数是单胞阈值处导模吸收图的互补累积分布，在五个全波锚点处保持为8×10⁻⁴。从恰好零磁化强度开始，分支选择仅由朗之万场单独决定，在16个随机种子下的占据率为0.502±0.004。
英文摘要
What a guided beam carries after passing through an all-optically switched magnetic film has not been computed, although such switching has been demonstrated on a silicon nitride waveguide with electrical readout. We close the chain for an integrated Si$_3$N$_4$/GdFeCo element, an 8 nm film on a 60 $μ$m waveguide, coupling a three-dimensional dispersive finite-difference time-domain solver to absorbed optical work, a four-temperature model, and stochastic two-sublattice Landau-Lifshitz-Bloch dynamics with a fluctuation-dissipation-consistent Langevin field, the magnetization feeding back into the gyrotropic permittivity that a second guided shot reads. Transmission, reflection and absorption are magnetization-blind, closing to 0.974-0.975 and shifting by at most 0.02 between saturated, demagnetized and multidomain films, because magnetization enters the dielectric tensor only through an antisymmetric element on which absorbed power depends at second order; the odd-in-magnetization polarimetry separates them by an order of magnitude in Faraday rotation and two in Kerr. The guided geometry levies a cost free-space measurement does not: a $-11.77^\circ$ geometric pedestal on the reflected channel, exceeding the $8.24^\circ$ rotation it hides. Referencing against a demagnetized film returns it to $0.063^\circ$. The transmitted mode carries a second signature in its lobe balance, needing no polarimetry. Calibrated pulses toggle 0.859 of the film from either saturated state across a $2.4\times$ fluence window, and the shortfall from unity is photonic rather than magnetic: the switched fraction is the complementary cumulative distribution of the guided-mode absorption map at the single-cell threshold, holding to $8\times10^{-4}$ at five full-wave anchors. From exactly zero magnetization, branch selection passes to the Langevin field alone, at occupancy $0.502 \pm 0.004$ over 16 seeds.
Comments46 pages, 10 figures. Supplementary material included as an ancillary file
