The Rise of Toroidal Electrodynamics and Spectroscopy.

Toroidal electrodynamics is now massively influencing research in toroidal (Marinov et al. , , 234; Basharin et al. , , 011036; Jeong et al. , , 1699) and anapole metamaterials (Basharin et al. , , 035104; Wu et al. , , 1920), optical properties of nanoparticles (Miroshnichenko et al. , , 8069; Gurvitz et al. , , 1800266), plasmonics (Ogut et al. , , 5239; Yezekyan et al. , , 6098), sensors (Gupta et al. , 121108; Ahmadivand et al. , , 108; Wang et al. , , 1295; Yao et al. , , 23), and lasers (Huang et al. , , 1237; Hwang et al. , , 3599), while a recent publication on toroidal optical transitions in hydrogen-like atoms (Kuprov et al. , , eabq7651) promises to launch a new chapter in spectroscopy. In this Viewpoint, we review these progresses.