Yang Jia-Yue, Cheng Tao, Fei Tianhao, Zhang Chun, Liu Linhua
Opt Lett. 2021 Sep 1;46(17):4244-4247. doi: 10.1364/OL.438993.
Perovskite has emerged as a relevant technological material for nano-photonics that confines light to subdiffraction geometry with remarkably wide spectral tunability. Yet, the influence of lattice vibrations on its surface phonon polaritons (SPhPs) and localized surface phonon resonances (LSPhRs) receives little attention, and the underlying physics still remains elusive. Here, we apply spectroscopic ellipsometry (SE) experiments and multiscale simulations spanning from first-principles to finite-difference time-domain (FDTD), and investigate the temperature influence on infrared dielectric functions, SPhPs and LSPhRs of . SE measurements find that the width of the Reststrahlen band lying between transverse and longitudinal oxygen-related optical phonons changes slightly, but infrared dielectric functions vary significantly as temperature increases. First-principles calculations confirm the coupling of the motion of oxygen atoms to incident photons, forming quasiparticles of SPhPs. FDTD simulations show that strong LSPhRs exist at 250 K in the nanodisks but dissipate as lattice vibration strengthens, mainly due to the reduced phonon relaxation lifetime. This work reveals the underlying physics of temperature influence on SPhPs and LSPhRs of and helps explore its potential applications as photonic resonators at high temperatures.
钙钛矿已成为纳米光子学中一种重要的技术材料，它能将光限制在具有显著宽光谱可调性的亚衍射几何结构中。然而，晶格振动对其表面声子极化激元（SPhPs）和局域表面声子共振（LSPhRs）的影响却很少受到关注，其 underlying physics 仍然难以捉摸。在这里，我们应用光谱椭偏仪（SE）实验以及从第一性原理到时域有限差分（FDTD）的多尺度模拟，并研究温度对红外介电函数、SPhPs 和 LSPhRs 的影响。SE 测量发现，位于横向和纵向氧相关光学声子之间的 Reststrahlen 带的宽度变化不大，但随着温度升高，红外介电函数变化显著。第一性原理计算证实了氧原子的运动与入射光子的耦合，形成了 SPhPs 的准粒子。FDTD 模拟表明，在 250 K 时，纳米盘中存在强烈的 LSPhRs，但随着晶格振动增强而消散，这主要是由于声子弛豫寿命缩短所致。这项工作揭示了温度对 SPhPs 和 LSPhRs 影响的 underlying physics，并有助于探索其作为高温光子谐振器的潜在应用。
