Ullah Kaleem, Habib Muhammad, Huang Lujun, Garcia-Camara Braulio
School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
Center for Micro and Nano Devices, Department of Physics, COMSATS University Islamabad, Park Road, Islamabad 44000, Pakistan.
Nanomaterials (Basel). 2019 Apr 3;9(4):536. doi: 10.3390/nano9040536.
The presence of a substrate is one of the most important limitations of the real application of the directional conditions. These conditions allow the control of the spatial distribution of light scattering of nanoparticles. While the zero-forward condition is quite sensitive to any change of the surrounding medium, like the substrate, the zero-backward scattering seems to be less sensitive and very stable under normal illumination. In this letter, the zero-backward scattering condition was investigated on a homogenous Cu₂O spherical subwavelength particle, both theoretically and experimentally. In particular, the influence of the substrate and the impinging direction on the angular distribution of light scattering under this directional condition were studied. We observed that the zero-backward scattering condition was also sensitive to the presence of a substrate beneath when a non-normal illumination was considered. We believe that our finding is quite interesting from a practical point of view and for the real implementation of directional scattering in various applications like cloaking, light-emitting devices, photovoltaic devices, bio-sensing, and many more.
基底的存在是定向条件实际应用中最重要的限制因素之一。这些条件允许控制纳米粒子光散射的空间分布。虽然零向前散射条件对周围介质（如基底）的任何变化相当敏感，但在正常照明下，零向后散射似乎不太敏感且非常稳定。在这封信中，我们对均匀的Cu₂O球形亚波长粒子在理论和实验上研究了零向后散射条件。特别地，研究了在这种定向条件下基底和入射方向对光散射角分布的影响。我们观察到，当考虑非垂直照明时，零向后散射条件对下方基底的存在也很敏感。我们认为，从实际应用的角度以及在诸如隐身、发光器件、光伏器件、生物传感等各种应用中定向散射的实际实现来看，我们的发现非常有趣。
