Topological Photonics and Topological Phononics
How the light, sound, and elastic waves propagate in a periodic structure is determined by the corresponding photonic or phonic band structures like electrons in the crystal. In the condensed matter physics, it is well recognized that the topological nature of the bands (band topology) plays crucial roles when a new phase of material emerges. In topological photonics and topological phonics, the concept of band topology is applied to light, sound, and elastic wave in periodic structures in order to realize novel functionalities, for instance, robust one-way waveguiding. We are engaged in research on semiconductor topological photonics based on semiconductor photonic crystal, aiming at uncovering the physics and the realization of laser, waveguide and others utilizing unique topological characteristics. In addition, we are also investigating topological elastic wave states for various applications.