Due to their distinctive properties, nanophotonics and topology have attracted a lot of attention. One area of focus is the examination of topological edge states (TESs). Because they are extremely resistant to mistakes and flaws, these states have received a lot of attention.
A powerful set of tools for the architectural design of photonic integrated circuits are TESs, which originate from topologically non-trivial phases. Pseudospin propagation in ring resonator arrays, one-way waveguides, mode-locked waveguides, and directional couplers are just a few of the intriguing optical effects and applications that have been discovered thanks to TES transport.
Techniques like adiabatic modulation, non-linear effects, and complex braiding have recently been explored by scientists as a means of expanding their efforts to manipulate TESs. Optical frameworks have shown a scope of captivating peculiarities, for example, edge-to-edge topological vehicles and tunable restrictions of topological states. Energy and information routing, non-linear photonics, and quantum computing are just a few of the cutting-edge technologies and applications that these phenomena have the potential to revolutionize.
While the current approaches concentrate on manipulating TESs, they have not yet given much thought to improving TESs’ interactions with one another. Researchers can enable the exchange of light energy between various parts of a topological lattice by improving the coupling between TESs. This will help control the transport of TESs in a more flexible manner.
A significant breakthrough was recently achieved by a group of researchers from China’s Huazhong University of Science and Technology (HUST) and the Wuhan National Laboratory for Optoelectronics (WNLO). They devised a novel strategy to effectively control TES transport for an optical channel switcher on a silicon-on-insulator (SOI) chip, as reported in Advanced Photonics.
Using the Landau-Zener (LZ) model, their research focused on edge-to-edge channel conversion in a four-level waveguide lattice. They developed an alternative, efficient, and dynamic strategy for modulating and controlling the transport of topological modes by taking advantage of the finite-size effect in an optical lattice with two units.
The waveguide cross section they utilized is like a 2D material called a Chern cover, which is known to have TESs. As the quantity of unit cells diminishes, the TESs advance as per the LZ model. The researchers were able to dynamically control the TESs and achieve nearly perfect channel conversion by utilizing the LZ single-band evolution principle.
Devices made of topological LZ nanophotonics have the potential to be utilized in a wide range of additional contexts. They are able to be utilized as switches that operate at particular wavelengths of light. By integrating LZ elements into various frameworks, it could be feasible to make chiral channel changes. This idea can likewise be extended to more intricate waveguide grids, taking into account considerably further developed gadgets.
The analysts found that these topological LZ optical gadgets are very strong, meaning they can function admirably in any event when certain boundaries are changed. This makes it possible to create useful devices like optical switches for routing networks on computer chips or waveguide-based devices that can combine or split multiple signals.
More information: Bing-Cong Xu et al, Topological Landau–Zener nanophotonic circuits, Advanced Photonics (2023). DOI: 10.1117/1.AP.5.3.036005
