Multi-frequency solitons in commensurate-incommensurate photonic moir\'e lattices

TL;DR

This paper predicts that photonic moiré patterns in nonlinear media enable the formation of parametric solitons with properties heavily influenced by the pattern's geometry, leading to lower power thresholds and broader phase-mismatch bandwidths.

Contribution

It introduces the concept of using moiré pattern geometry to control parametric soliton formation in quadratic nonlinear media, revealing new effects on phase-matching and power thresholds.

Findings

Reduced soliton excitation threshold in moiré patterns

Shifted phase-matching conditions to eigenmode edges

Broadened phase-mismatch bandwidth for soliton generation

Abstract

We predict that photonic moir\'e patterns created by two mutually twisted periodic sublattices in quadratic nonlinear media allow the formation of parametric solitons under conditions that are strongly impacted by the geometry of the pattern. The question addressed here is how the geometry affects the joint trapping of multiple parametrically-coupled waves into a single soliton state. We show that above the localization-delocalization transition the threshold power for soliton excitation is drastically reduced relative to uniform media. Also, the geometry of the moir\'e pattern shifts the condition for phase-matching between the waves to the value that matches the edges of the eigenmode bands, thereby shifting the properties of all soliton families. Moreover, the phase-mismatch bandwidth for soliton generation is dramatically broadened in the moir\'e patterns relative to latticeless structures.