Polaritons are widely investigated quasiparticles with fundamental and technological significance due to their unique properties. They have been studied most extensively in semiconductors when photons interact with various elementary excitations. However, other strongly coupled excitations demonstrate similar dynamics. Specifically, when magnon and phonon modes are coupled, a hybridized magnon–phonon quasiparticle can form. Here, we report on the direct observation of coupled magnon–phonon dynamics within a single thin nickel nanomagnet. We develop an analytic description to model the dynamics in two dimensions, enabling us to isolate the parameters influencing the frequency splitting. Furthermore, we demonstrate tuning of the magnon–phonon interaction into the strong coupling regime via the orientation of the applied magnetic field.

极化子由于其独特的性质而被广泛研究，具有基础和技术意义。当光子与各种基本激发相互作用时，已经在半导体中对它们进行了最广泛的研究。但是，其他强耦合激发也表现出相似的动力学。具体地说，当磁振子和声子模式耦合时，会形成杂化的磁振子-声子准粒子。在这里，我们报告了在单个薄镍纳米磁体中直接观察到的磁振子-声子动力学耦合的结果。我们开发了一个解析描述来对二维动力学进行建模，从而使我们能够分离出影响频率分割的参数。此外，我们展示了通过施加磁场的方向将磁振子-声子相互作用调节到强耦合状态的过程。