The Möbius strip, a fascinating loop structure with one-sided topology, provides a rich playground for manipulating the non-trivial topological behaviour of spinning particles, such as electrons, polaritons and photons, in both real and parameter spaces. For photons resonating in a Möbius-strip cavity, the occurrence of an extra phase—known as the Berry phase—with purely topological origin is expected due to its non-trivial evolution in parameter space. However, despite numerous theoretical investigations, characterizing the optical Berry phase in a Möbius-strip cavity has remained elusive. Here we report the experimental observation of the Berry phase generated in optical Möbius-strip microcavities. In contrast to theoretical predictions in optical, electronic and magnetic Möbius-topology systems where only Berry phase π occurs, we demonstrate that a variable Berry phase smaller than π can be acquired by generating elliptical polarization of resonating light. Möbius-strip microcavities as integrable and Berry-phase-programmable optical systems are of great interest in topological physics and emerging classical or quantum photonic applications.
V. M. Fomin, O. V. Dobrovolskiy
Appl. Phys. Lett. 120, 090501 (2022)
In recent years, superconductivity and vortex matter in curved 3D nanoarchitectures have turned into a vibrant research avenue because of the rich physics of the emerging geometry- and topology-induced phenomena and their prospects for applications in (electro)magnetic field sensing and information technology. While this research domain is still in its infancy, numerous theoretical predictions await their experimental examination. In this Perspective, after a brief introduction to the topical area, we outline experimental techniques capable of fabrication of curved 3D nanostructures and review selected own results on the intertwined dynamics of Meissner currents, Abrikosov vortices, and slips of the phase of the superconducting order parameter therein. We share our vision regarding prospect directions and current challenges in this research domain, arguing that curved 3D nanoarchitectures open up a direction in superconductors' research and possess great potential for magnetic field sensing, bolometry, and fluxonic devices.
to be continued...