Recent advances in magnetically responsive photonic crystals assembled by anisotropic building blocks: Synthesis, challenges and outstanding applications

Photonic crystals (PC) are periodically ordered dielectric materials with a wide range of tunable optical properties and are the basis for most studies of responsive optical systems. However, current challenges in photonic crystal performance include limited tunability of the band gap, slow response to external stimuli, irreversibility, and difficulty in integration into existing optical systems. Magnetically responsive photonic crystals (MRPC) can effectively improve these problems and simplify the structure of responsive photonic crystals. Therefore, MRPC has become a research hotspot, but most of the current research focuses on isotropic (spherical) particles. So far, no one has systematically summarized the magnetic photonic crystals prepared by nanoparticles with different shapes and compared them with spherical photonic crystals. This paper first introduces non-spherical nanoparticles as the basic unit for constructing magnetic photonic crystals. These anisotropic building blocks will inject new blood into the magnetic photonic crystal. In addition, we also describe the preparation and applications of magnetically responsive photonic crystals and categorically explore the characteristics of magnetically responsive photonic crystals assembled by anisotropic building blocks. Finally, we summarize the challenges in the field of MRPC and provide an outlook for their further development in the next stage.