Analysis of the Substrate Effect on the Zero-Backward Scattering Condition of a Cu2O Nanoparticle under Non-Normal Illumination

Abstract

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.

Kerker Conditions upon Lossless, Absorption, and Optical Gain Regimes

“…Consequently, the aforementioned backscattering anomalies could also be measured on larger dielectric particles. Interestingly, the absence of backscattered light emerges at the first Kerker condition for dipolar particles regardless of the incoming polarization [10][11][12][13]. On the other hand, for cylindrically symmetric particles, the absence of backscattered light follows from the preservation of EM helicity [14][15][16][17][18].…”

“…On the other hand, the second Kerker condition does not appear for ℑfmg ¼ 0, in agreement with Eq. (13). In fact, it arises if and only if optical gain is being pumped onto the system.…”

Resonant Scattering Manipulation of Dielectric Nanoparticles

“…Cuprous oxide (Cu 2 O) materials, with a refractive index typically close to 2.7, was initially developed as a photocatalyst material given its electronic properties. [ 41,140,141 ] However, in recent years, Cu 2 O spheres have been further employed as nanoantennas in the visible range because large‐scale production of these spheres with a uniform diameter can be easily synthesized through wet‐chemistry methods. [ 142,143 ] Their role as Mie‐type resonators dates back to 2015 when Lin's group experimentally and theoretically demonstrated that the electric and magnetic modes (up to quadrupolar) in Cu 2 O spheres can spectrally overlap.…”

Substrate-Modulated Electric and Magnetic Resonances of Lithium Niobite Nanoparticles Illuminated by White Light

“…These nanoparticles can be utilized as building blocks for nanoantenna in the visible range. In contrast to the high refractive index nanoparticles, the nanoparticles with a refractive index around 1.7-3 also support ED and MD resonances [20][21][22][23][24][25][26]. In this case, the spectra of the ED and MD resonances tend to largely overlap with each other, which enables forward scattering to occur at the peak of total scattering spectra.…”