Jinlong Lu is in the lab. Thomas Zentgraf is from Paderborn University.
Light is an information carrier for optical computer chips and the next generation of quantum computers. The control of its interaction with other light and its guidance around sharp corners are the focus of research worldwide. Scientists at Paderborn University have demonstrated the spatial confinement of a light wave to a point smaller than the wavelength. These are artificial materials that can be used to manipulate light. The state is important for quantum chips. The findings have been published.
The properties of topological crystals are unaffected by deviations and disturbances. The effects needed for light manipulation are fragile and can be affected by defects in the material structure, but the conditions are protected from this. Features that are crucial for future light-based technologies are allowed by the topological structures.
The propagation of waves is influenced by the influence of photonic crystals and an optical band gap. Some of the light is reflected back, while others are not. You can prevent this by using light states that span a wide range of crystals. Back reflection poses a major problem because it leads to unwanted feedback. Large-scale integration of optical chips is hampered by loss during propagation. Professor Thomas Zentgraf is the head of the Ultrafast Nanophotonics research group at Paderborn University.
The concept, which has its origins in solid-state physics, has led to many applications. It was recently proven that a crystal with a dislocation in the periodic structure also has special properties, and that it also supports strongly spatially localized light states. Changes in the parameters do not affect the protected properties. Zentgraf says that localized light states are useful for integration of quantum chips. Weak topological states are special states for the light that result from the formation of the crystal structure.
Researchers from Paderborn University and RWTH Aachen University used a special near-field optical microscope to demonstrate the existence of light states in topological structures. Jinlong Lu is the lead author of a paper that shows how the flexibility of weak topology can produce a strong optical field. Zentgraf says that the study shows a viable strategy for achieving a zero-dimensional state for light. The researchers have shown that near-field microscopy is a useful tool for the study of topological structures.
The findings show how to use strong optical light states based on weak topology. The experiment to produce robust and active topological photonic elements could be done with phase- change materials with a tunable Refractive index. Zentgraf says that they are working on concepts to equip the dislocation centers in the crystal structure with special quantum emitters for single photon generation, which could be used in future optical quantum computers.
Jinlong Lu and his team observed 0D subwavelength-localized modes at 100 THz protected by weak topology. There is a DOI for this.
Science Advances has journal information.
There are artificial material states on smallest length scales.
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