Center for Nanophotonics, AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, PO Box 94485, 1090 GL Amsterdam, The Netherlands.
Phys Rev Lett. 2018 May 18;120(20):206101. doi: 10.1103/PhysRevLett.120.206101.
The polarizability α determines the absorption, extinction, and scattering by small particles. Beyond being purely set by scatterer size and material, in fact polarizability can be affected by backaction: the influence of the photonic environment on the scatterer. As such, controlling the strength of backaction provides a tool to tailor the (radiative) properties of nanoparticles. Here, we control the backaction between broadband scatterers and a single mode of a high-quality cavity. We demonstrate that backaction from a microtoroid ring resonator significantly alters the polarizability of an array of nanorods: the polarizability is renormalized as fields scattered from-and returning to-the nanorods via the ring resonator depolarize the rods. Moreover, we show that it is possible to control the strength of the backaction by exploiting the diffractive properties of the array. This perturbation of a strong scatterer by a nearby cavity has important implications for hybrid plasmonic-photonic resonators and the understanding of coupled optical resonators in general.
极化率α决定了小颗粒的吸收、消光和散射。实际上，极化率不仅纯粹由散射体的大小和材料决定，还可以受到后向作用的影响：光子环境对散射体的影响。因此，控制后向作用的强度为调整纳米粒子的（辐射）性质提供了一种工具。在这里，我们控制了宽带散射体和高品质腔中单模之间的后向作用。我们证明了微环谐振器的后向作用会显著改变纳米棒阵列的极化率：由于从纳米棒散射并通过环谐振器返回的场使棒去极化，因此极化率被重新归一化。此外，我们还表明，通过利用阵列的衍射性质，可以控制后向作用的强度。这种附近腔对强散射体的微扰对混合等离子体-光子谐振器以及一般耦合光谐振器的理解具有重要意义。
