近日，奥地利维也纳工业大学的Stefan Rotter及其研究团队取得一项新进展。经过不懈努力，他们成功实现用于时变光子介质中波前整形的伪幺正弗洛凯散射矩阵。相关研究成果已于2024年11月18日在国际知名学术期刊《物理评论A》上发表。

该研究团队展示如何通过满足伪幺正关系的静态弗洛凯散射矩阵，来准确描述有限弗洛凯介质的散射特性。这一代数性质源于波作用的守恒，对此研究人员构建了相应的连续性方程。利用这一弗洛凯散射矩阵，研究人员进一步展示了如何将基于维格纳-史密斯算子的波前整形概念，从静态系统扩展到弗洛凯系统。

研究表明，对应弗洛凯维格纳-史密斯矩阵的本征态是光脉冲，这些光脉冲在空间和时间自由度上都得到了最优整形，适用于时变介质的光学微操纵。

据悉，时变介质中的波动物理为波的控制，提供了诸多在静态介质中无法实现的机会。尤其是具有周期性时间调制的弗洛凯系统，当前备受关注。

附：英文原文

Title: Pseudounitary Floquet scattering matrix for wave-front shaping in time-periodic photonic media

Author: David Globosits, Jakob Hüpfl, Stefan Rotter

Issue&Volume: 2024/11/18

Abstract: The physics of waves in time-varying media provides numerous opportunities for wave control that are unattainable with static media. In particular, Floquet systems with a periodic time modulation are currently of considerable interest. Here we demonstrate how the scattering properties of a finite Floquet medium can be correctly described by a static Floquet scattering matrix, which satisfies a pseudounitary relation. This algebraic property is a consequence of the conservation of wave action for which we formulate here a continuity equation. Using this Floquet scattering matrix, we further demonstrate how it can be used to transfer concepts for wave-front-shaping based on the Wigner-Smith operator from static to Floquet systems. The eigenstates of the corresponding Floquet Wigner-Smith matrix are shown to be light pulses that are optimally shaped in both their spatial and temporal degrees of freedom for the optical micromanipulation of time-varying media.

DOI: 10.1103/PhysRevA.110.053515

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.053515