Generation and probing of 3D helical lattices with tunable helix pitch and interface

Switching via wave interaction in topological photonic lattices

A honeycomb Floquet lattice with helically rotating waveguides and an interface separating two counter-propagating subdomains is analyzed. Two topologically protected localized waves propagate unidirectionally along the interface. Switching can occur when these interface modes reach the edge of the lattice and the light splits into waves traveling in two opposite directions. The incoming mode, traveling along the interface, can be adjusted and routed entirely or partially along either lattice edge with the switching direction based on a suitable mixing of the interface modes.

Josephson oscillations of edge quasi-solitons in a photonic-topological coupler

We introduce a scheme of a photonic coupler built of two parallel topological-insulator slab waveguides with the intrinsic Kerr nonlinearity, separated by a lattice spacing. Josephson oscillations (JOs) of a single edge quasi-soliton (QS) created in one slab, and of a pair of QSs created in two slabs, are considered. The single QS jumping between the slabs is subject to quick radiative decay. However, the JOs of the co-propagating QS pair may be essentially more robust, as one QS absorbs dispersive waves emitted by the other. The most robust JO regime is featured by the pair of QSs with phase shift π between them.

Lasing from an Organic Micro-Helix

Organic solid-state semiconductor lasers are attracting ever-increasing interest for their potential application in future photonic circuits. Despite the great progress made in recent years, an organic laser from 3D chiral structures has not been achieved. Now, the first example of an organic nano-laser from the micro-helix structure of an achiral molecule is presented. Highly regular micro-helixes with left/right-handed helicity from a distyrylbenzene derivative (HM-DSB) were fabricated and characterized under microscope spectrometers. These chiral micro-helixes exhibit unique photonic properties, including helicity-dependent circularly polarized luminescence (CPL), periodic optical waveguiding, and length-dependent amplified spontaneous emission (ASE) behavior. The successful observation of laser behavior from the organic micro-helix extends our understanding to morphology chirality of organic photonic materials and provides a new design strategy towards chiral photonic circuits.

Bragg solitons in topological Floquet insulators

We consider a topological Floquet insulator consisting of two honeycomb arrays of identical waveguides having opposite helicities. The interface between the arrays supports two distinct topological edge states, which can be resonantly coupled by additional weak longitudinal refractive index modulation with a period larger than the helix period. In the presence of Kerr nonlinearity, such coupled edge states enable topological Bragg solitons. Theory and examples of such solitons are presented.