Extraordinary transmission caused by symmetry breaking

Experimental evidence of spontaneous symmetry breaking in intracavity type-II second harmonic generation with triple resonance

We describe an experiment showing a spontaneous symmetry breaking phenomenon between the intensities of the ordinary and extraordinary components of the fundamental field in intracavity type-II harmonic generation. It is based on a triply resonant dual cavity containing a type II phase matched $χ^{(2)}$ crystal pumped at the fundamental frequency $ω_0$. The pump beam generates in the cavity a second harmonic mode at frequency $2ω_0$ which acts as a pump for frequency degenerate type II parametric down conversion. Under operating conditions which are precisely symmetric with respect to the ordi…

Resonant Asymmetric All-Dielectric Metasurface for Boosting Third-Harmonic Generation

Resonant metasurfaces have received extensive attention due to their sharp spectral feature and extraordinary field enhancement. In this work, by breaking the in-plane symmetry of silicon nanopillars, we achieve a sharp Fano resonance. The far-field radiation and near-field distribution of metasurfaces are calculated and analyzed to further uncover the resonant performance of metasurfaces. Moreover, the theoretical derivation and simulation exhibit an inverse quadratic dependence of Q-factors on asymmetry parameters, revealing that the resonance is governed by the symmetry-protected bound stat…

Switch between the types of the symmetry breaking bifurcation in optically induced photorefractive rotational double-well potential

We study the possibility of switching the types of symmetry breaking bifurcation (SBB) in the cylinder shell waveguide with helical double-well potential along propagation direction. This model is described by the one-dimensional nonlinear Schrödinger (NLS) equation. The symmetry- and antisymmetry-breakings can be caused by increasing the applied voltage onto the waveguide in the self-focusing and -defocusing cases, respectively. In the self-focusing case, the type of SBB can be switched from supercritical to subcritical. While in the self-defocusing case, the type of SBB can not be switched b…

Transient optical symmetry breaking for ultrafast broadband dichroism in plasmonic metasurfaces

Ultrafast nanophotonics is an emerging research field aimed at the development of nanodevices capable of light modulation with unprecedented speed. A promising approach exploits the optical nonlinearity of nanostructured materials (either metallic or dielectric) to modulate their effective permittivity via interaction with intense ultrashort laser pulses. While the ultrafast temporal dynamics of such nanostructures following photoexcitation has been studied in depth, sub-ps transient spatial inhomogeneities taking place at the nanoscale have been so far almost ignored. Here we theoretically pr…

Left-right asymmetry in an optical nanofiber

Symmetry breaking effect for left- and right-handed circularly polarized light beams propagating in a rotationally symmetric graded-index optical fiber is presented. It is shown that a left-right asymmetry manifested as an unequal transmission for opposite circular polarizations occurs due to spin-to-spin angular momentum conversion caused by tensor interaction.

光力学系统中噪声影响下的自发 PT 对称性破缺相变

Spontaneous PT-symmetry breaking transitions under the influence of noise in an optomechanical system

本文研究含例外点的光力学系统，发现例外点以下 PT 对称相与非 PT 对称相共存，噪声可诱发两相随机转变及光子、声子模式强度突变。