Impedance-Matched, Double-Zero Optical Metamaterials Based on Weakly Resonant Metal Oxide Nanowires

Abstract

Artificial optical metamaterial with a zero index of refraction holds promise for many diverse phenomena and applications, which can be achieved with vacuum (or related) surface impedance and materials in the optical domain. Here, we propose simple metal-oxide nanorods as meta-atoms on the basis of an effective medium approach, based on their weak overlapping (electric/magnetic) resonances. We thus studied the optical properties of TiO 2 nanowire arrays with a high-filling fraction through their photonic band structure, which exhibits a double-degeneracy point without a band gap at the center of the Brillouin zone. Various configurations are considered that reveal their performance over a reasonable range of incident wave vectors as impedance-matched, double-zero, bulk (low-loss) metamaterials.

Engineering bound states in the continuum at telecom wavelengths with non-Bravais lattices

“…To confirm our intuitive explanation of the underlying physical mechanism, we have investigated theoretically the extinction of the arrays using a CEMD model. 52,58 We extract numerically the polarizability of electric and magnetic dipoles from the single disks, and calculate analytically 1 − T (equivalent to the experimental extinction, since T is the specular transmittance) when the dipoles are arranged in an infinite lattice. The calculations shown in Figs.…”

Спонтанная Эмиссия В Утекающие Моды Нанопроводов

“…Кроме этого, при анализе процессов излучения в нанопроводе иногда ограничиваются описанием взаимодействия эмиттера с волноводными модами, игнорируя излучение в свободное пространство (вытекающие моды), что, возможно, связано с наличием фундаментальной волноводной моды HE11, которая существует при любом значении радиуса цилиндрического волновода. Необходимо учитывать, что при малых радиусах волновода вероятность эмиссии в волновую моду очень мала [17][18][19][20][21], и основной вклад в эмиссию вносят утекающие моды.…”

Spontaneous emission in leaky modes of nanowires

“…Besides, analysis of emission processes in nanowire sometimes is limited by describing the interaction of the emitter with waveguide modes, ignoring emission into free space (leaking modes), which is possibly due to the presence of a fundamental waveguide mode HE11, which exists at any value of the radius of a cylindrical waveguide. It should be taken into account that at small waveguide radius the probability of emission into the wave mode is very small [17][18][19][20][21], and the main contribution to the emission is made by leaking modes.…”