Nonlinear Bound States in the Continuum in One-Dimensional Photonic Crystal Slab

TL;DR

This paper investigates the nonlinear optical behavior of a one-dimensional photonic crystal slab near bound states in the continuum, revealing multistability, self-tuning, and symmetry breaking phenomena with potential applications in integrated photonics.

Contribution

It provides the first analytical and numerical study of nonlinear BIC phenomena in 1D photonic crystals with Kerr nonlinearity, including predictions of multistability and symmetry breaking at low power levels.

Findings

Observation of multistable behavior in nonlinear BICs

Demonstration of self-tuning of BIC to incident wave frequency

Identification of symmetry breaking in BICs at low pump power

Abstract

Optical bound state in the continuum (BIC) is characterized by infinitely high quality factor resulting in drastic enhancement of light-matter interaction phenomena. We study the optical response of a one-dimensional photonic crystal slab with Kerr focusing nonlinearity in the vicinity of BIC analytically and numerically. We predict a strong nonlinear response including multistable behaviour, self-tuning of BIC to the frequency of incident wave, and breaking of symmetry protected BIC. We show that all of these phenomena can be observed in silicon photonic structure at the pump power of several $\mu$W/cm$^2$. We also analyze the modulation instability of the obtained solutions and the effect of the finite size of the structure on the stability. Our findings have strong implications for nonlinear photonics and integrated optical circuits.