Topological Points and Lines in Photonic Momentum Space

Date

Aug 12, 2019

Time

10:00 AM - 11:00 AM

Speaker

Prof. Rongjuan Liu

Affiliation

Institute of Physics, Chinese Academy of Sciences

Language

en

Main Topic

Materialien

Host

Kristina Krummer

Description

The well-known degenerate points and lines in momentum space are Dirac points, Weyl points and nodal lines, etc. for their topological properties. In this talk, I will present some of our works on these topological states in photonic regime. Weyl points are three-dimensional degenerate points. Although many materials and structures with Weyl points are reported since Weyl points were first discovered in 2015, all these Weyl points are not ideal for their energy are not at the same energy and they are always accompanied with some other trivial bands. We designed and realized the ideal Weyl points in a three-dimensional photonic crystal composed of saddle-shaped metallic coils and observed their surface states shown as helicoidal shape. In contrast to degenerate points allowing for few structure variations, degenerate lines, usually called as nodal lines, have various configurations, such as nodal rings, nodal chains, nodal links and nodal knots. However, nodal lines are much less explored because of the lack of an ideal experimental realization. We theoretically predicted and experimentally observed nodal chains in a three-dimensional metallic-mesh photonic crystal. These topological systems provide photonic platform for exploring new topological properties and developing possible topological devices.

Links

• Seminars at the IFW

Last modified: Aug 12, 2019, 12:08:22 AM