Topological and Chiral Photonics
Topological and Chiral Photonics is a rapidly growing field that draws inspiration from topological insulators, but applies similar concepts to manipulate and control the flow of light.
Researchers are investigating how to engineer photonic structures with topologically protected modes, such as edge states, that are robust against defects and scattering.
One of the central ideas in topological photonics is the concept of topological protection. Topological insulators in photonics are designed to support robust edge states or modes that are immune to defects and scattering.
These states are protected by non-trivial topological invariants (such as the Chern number or the Zak phase), ensuring their stability in the presence of imperfections. This can be a great advantage in integrated photonic implementations because of the inevitable imperfections arising from processing.
Although only a few years old the field has taken off rapidly with demonstrations in different systems.
In recent years in a collaboration with IBM Reserach Zurich and Hanbat University in South Korea, we have worked on developing new concepts for nanophotonic topological lasers. In [1 & 3 - linkto belwo] we have introduced a novel 1D nanorod cavity design, with underlying lattice structure inspired by the Su-Schrieffer-Heeger (SSH) model.
The SSH model describes a dimerized lattice formed through alternating the bond strength between individual lattice sites, that allows to amplify the topological interface mode.
In our case this is achieved by deterministic placement of gain material within the topological lattice, as illustrated in Fig. xx where the selective epitaxy process enables interlaced Si and InGaAs nanorods embedded within the same topological lattice.
This resulted in the first demonstration of a single-mode laser in the telecom band using the concept of amplified topological modes23, accepted for ACS Photonics.
Relevant publications:
1) Single-Mode Laser in the Telecom Range by Deterministic Amplification of the Topological Interface Mode
M Scherrer, CW Lee, H Schmid, KE Moselund
ACS photonics 11 (3), 1006-1011
2) Phase of Topological Lattice with Leaky Guided Mode Resonance
H Choi, S Kim, M Scherrer, K Moselund, CW Lee
Nanomaterials 13 (24), 3152
3) Single-mode emission from a topological lattice with distributed gain and dielectric medium
M Scherrer, S Kim, H Choi, H Schmid, CW Lee, KE Moselund
2022 Optical Fiber Communications Conference and Exhibition (OFC), 1-3