Topological insulator materials for optics: Research progress and prospects

Topological insulators (TIs) are emerging quantum materials with insulating bulk and topologically protected metallic surface states. The electrons in the surface state are massless Dirac fermions with full spin polarization and are protected from backscattering. Due to this unique electronic structure, they exhibit novel optoelectronic properties and a variety of quantum effects. These distinctive properties make TIs potential candidates for applications in low-energy-consumption electronic devices, quantum computing, and low-loss optoelectronic devices. The unique optical properties of TIs have advanced considerably the development of plasmon-enhanced photovoltaic devices, ultrathin holograms, optical angular momentum nanometrology, and planar lenses. These developments underscore how TIs are setting new benchmarks in the optoelectronic domain and demonstrate the broad applicability of these materials. This comprehensive overview of recent progress in the field of TI optics emphasizes the wide range of applications of various compounds and showcases their exceptional performance. We introduce the optical properties of TIs and explore the performances of many devices based on these materials. On the latter subject, we discuss the innovative structures on which they are based, highlight potential directions for experimental innovations and device development, and consider their significance in both fundamental research and practical applications.