Related Experiment Video
Updated: Feb 6, 2026
11:08
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
19.5K
Photonic Weyl phase transition in dynamically modulated brick-wall waveguide arrays
Optics Express
|August 19, 2018
Summary
Researchers explore topological phase transitions between Type-I and Type-II Weyl points (WPs) in a novel 3D lattice. This work enables control over wave propagation in both spatial and frequency domains.
Area of Science:
- Condensed Matter Physics
- Photonics
- Topological Materials
Background:
- Weyl points (WPs) are crucial topological defects in band structures.
- Distinguishing between Type-I and Type-II WPs is essential for understanding topological phenomena.
- Photonic systems offer a versatile platform for simulating complex quantum phenomena.
Purpose of the Study:
- To investigate the topological phase transition between Type-I and Type-II Weyl points.
- To realize this transition in a composite 3D photonic lattice using dynamic modulation.
- To explore the resulting surface states and their unique propagation characteristics.
Main Methods:
- Fabrication of a composite 3D lattice combining a 2D brick-wall waveguide array and a synthetic frequency dimension.
- Application of dynamic modulation with varying amplitudes and phases to break parity or time-reversal symmetry.
- Analysis of Fermi-arc surface states and their directional propagation.
Main Results:
- Successful realization of the topological phase transition between Type-I and Type-II WPs.
- Emergence of two Fermi-arc surface states with opposite (Type-I) or same (Type-II) propagation directions.
- Observation of bidirectional and unidirectional frequency shifts for optical modes.
- Identification of a flat band with vanished group velocity at the phase transition point.
Conclusions:
- The study demonstrates a method to achieve distinct topological phases within a single photonic structure.
- This provides new avenues for controlling wave transport in both spatial and frequency dimensions.
- The findings have implications for designing advanced optical devices and topological photonic systems.
Related Concept Videos
02:31Phase Transitions
23.2K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
23.2K
02:33Phase Transitions: Sublimation and Deposition
20.2K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
20.2K
02:39Phase Transitions: Vaporization and Condensation
21.5K
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
21.5K
02:39Phase Transitions: Melting and Freezing
15.2K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
15.2K
01:20Spanning Openings in Brick Walls
580
In brick wall construction, supporting structures are crucial for openings like windows and doors to maintain the integrity and support the weight of the wall above. These supports include lintels, corbels, and arches, each serving specific structural purposes.
Lintels are primary supports used to span openings and can be crafted from materials such as reinforced concrete, steel-reinforced brick masonry, or simple steel angles. These are straightforward to install and are typically concealed...
Lintels are primary supports used to span openings and can be crafted from materials such as reinforced concrete, steel-reinforced brick masonry, or simple steel angles. These are straightforward to install and are typically concealed...
580
01:14Bricks
440
Bricks, a fundamental building material, are crafted from fired clay and exhibit a range of shapes, sizes, and colors. The production process starts with extracting local clay or shale, which is then crushed, ground, and screened for a fine texture. The refined material is blended with water, creating a pliable mixture that can be formed into bricks using one of three processes: soft mud, dry press, or stiff mud methods.
Soft mud bricks are shaped in molds with high moisture content and can be...
Soft mud bricks are shaped in molds with high moisture content and can be...
440