Prof. Lingbo Xia from Hunan University gave a talk entitled ‘Photonic Hourglass Nodal Line’ at the Faculty of Science and Technology on 3rd August 2021. At the seminar, Prof. Xia shared his/her latest research results in the field of topological metamaterials. From the concept of topological materials in solid state physics, Prof. Xia introduced the recent development in topological photonics materials, especially the photonic hourglass nodal line effect based on metamaterials. The nodal line semimetal shows linear degeneracy in the momentum space. Theoretically, the nodal line degeneracy can be broken or removed breaking symmetry, so the nodal line degeneracy is relatively weak. Hourglass nodal line with hourglass shaped four bands go around a closed trajectory and the hourglass nodal line degeneracy is unbreakable when preserving symmetry. Relevant theoretical and experimental results of photonic hourglass nodal line were presented and discussed at this seminar.

Prof. Lingbo Xia received his Ph.D. degree from Tianjin University in 2020. During 2016-2018, he visited the University of Birmingham for two years and the University of Texas at Austin for half year. He is currently an Associate Professor in the School of Physics and Electronics, Hunan University.