Abstract

This Letter is devoted to pointing out a specific feature of the finite-difference-time-domain (FDTD) method through the study of nano-structures supporting geometrical symmetry-protected modes that cannot be excited at certain conditions of illumination. The spatial discretization performed in the FDTD algorithm naturally leads to breaking this symmetry and allows the excitation of these modes. The quality factors of the corresponding resonances are then directly linked to the degree of symmetry breaking, i.e., the spatial grid dimension, even though the convergence criteria of the FDTD are fulfilled. This finding shows that the FDTD must be handled with great care and, more importantly, that very huge quality-factor resonances can be achieved at the cost of nanometer-scale mastered fabrication processes.

© 2020 Optical Society of America

Polarization-independent narrowband transmittance filters via symmetry-protected modes in high contrast gratings

Michael Barrow and Jamie Phillips
Opt. Lett. 45(15) 4348-4351 (2020)

Excitation of symmetry protected modes in a lithium niobate membrane photonic crystal for sensing applications

Ayman Hoblos, Miguel Suarez, Nadège Courjal, Maria-Pilar Bernal, and Fadi I. Baida
OSA Continuum 3(11) 3008-3018 (2020)

Hidden linear optical response reveals crystalline symmetry

X. D. Zhu and Hang Zhang
Opt. Lett. 45(8) 2439-2442 (2020)

Design of an efficient single photon source from a metallic nanorod dimer: a quasi-normal mode finite-difference time-domain approach

Rong-Chun Ge and S. Hughes
Opt. Lett. 39(14) 4235-4238 (2014)

Asymmetric localization and symmetric diffraction-free transmission in synthetic photonic lattice with anti-parity-time symmetry

Yanan Dai, Zengrun Wen, Kaiwen Ji, Zhenjuan Liu, Haohao Wang, Zhiqing Zhang, Yuanmei Gao, Baole Lu, Yishan Wang, Xinyuan Qi, and Jintao Bai
Opt. Lett. 45(11) 3099-3102 (2020)