标题： 扩散介质中的脉冲控制广义时间反转 显示英文标题

标题： Generalized Time-Reversal for Pulse Control in Diffusive Media

摘要： 时间反演对称性允许波通过复杂介质追溯其路径并在原点重新聚焦。 然而，散射波的不完全捕获和反演通常会限制脉冲的再压缩。 我们通过引入一种广义的时间反演框架来解决这一挑战，该框架将最优源模式确定为捕获和反演波能量最大的那个。 在二维扩散波导中，我们使用时空调制重建了对应于这种最优源的时间反演波前，与未调制的脉冲相比，峰值传输功率提高了35倍。 内部时空测量揭示了一个“加载和释放”过程，在此过程中，能量在介质中积累，然后突然释放。 此外，对这一脉冲进行时间反演可以实现深入散射介质的能量传递。 广义的时间反演为强散射介质中的短脉冲控制开辟了新的可能性，应用范围从光遗传学到随机激光放大。 显示英文摘要

摘要： Time-reversal symmetry allows waves to retrace their paths through complex media and refocus at their origin. However, incomplete capture and reversal of scattered waves often limits pulse recompression. We address this challenge for spatially extended sources by introducing a generalized time-reversal framework, which identifies the optimal source pattern as the one that maximizes the energy of the waves that are captured and reversed. In a two-dimensional diffusive waveguide, we reconstruct the time-reversed wavefront corresponding to this optimal source using spatiospectral shaping, leading to a 35-fold enhancement in peak transmitted power compared to an unmodulated pulse. Internal spatiotemporal measurements reveal a ``loading and firing" process, in which energy accumulates within the medium and then is released abruptly. Moreover, time-reversing this burst enables deep energy delivery into the scattering medium. Generalized time-reversal opens new possibilities for short-pulse control in strongly-scattering media, with applications ranging from optogenetics to random laser amplification.