Even-order optical harmonics generated from centrosymmetric-material metasurfaces
Abstract
Generation of even-order optical harmonics requires noncentrosymmetric structures being conventionally observed in crystals lacking the center of inversion. In centrosymmetric systems, even-order harmonics may arise, e.g., at surfaces but such effects are usually very weak. Here we observe optical harmonics up to 4-th order generated under the normal incidence from centrosymmetric dielectric metasurfaces empowered by resonances. We design silicon metasurfaces supporting optical quasibound states in the continuum and guided-mode resonances, and demonstrate the enhancement of second-harmonic signals by over three orders of magnitude compared to nonresonant thin films. Under the optimal conditions, the brightness of the second harmonic approaches that of the third harmonic, and the 4th-order harmonic becomes detectable.
Cite
@article{arxiv.2403.19385,
title = {Even-order optical harmonics generated from centrosymmetric-material metasurfaces},
author = {Pavel Tonkaev and Fangxing Lai and Sergey Kruk and Qinghai Song and Michael Scalora and Kirill Koshelev and Yuri Kivshar},
journal= {arXiv preprint arXiv:2403.19385},
year = {2024}
}