Our new paper titled “Double-bowl State in photonic Dirac nodal line semimetal” is published in Light: Science & Applications.
In this work we investigate a photonic Dirac nodal line semimetal (DNLS), which is not a trivial spinless extension of the electronic DNLS, and thus indicates the possibility of identifying new mechanisms unique for photonics to protect topological phases. We provide a stringent photonic realization of type-II DNLS with a ring shape four-fold band degeneracy. We measure the dispersion of the DNLS along relevant directions and thus provide the smoking gun for the realization of photonic DNLS. We deposit a silver film on top of this photonic DNLS and identify the double-bowl surface states possessed by this composite system through angle-resolved spectra.
Our system can serve as an ideal platform for investigating phenomena that require large field enhancement as well as manipulating light with an arbitrary polarization while studying polarization-sensitive light-matter interactions.
Fig. 1. Photonic Dirac nodal line semimetal.
Fig. 2. Experimental observation of photonic Dirac nodal ring.