The increase in refractive indices (n) of materials is vital for advancing optical technologies. Monolithic lithography has significantly improved the refractive indices of semiconductors like silicon, germanium, and gallium arsenide, reaching n values of around 4.0. However, surpassing this natural upper limit could revolutionize light–matter interactions and expand their applications. Our research presents a soft self-assembly method of polyhedral gold (Au) colloids to achieve exceptionally high n values. The interfacial assembly of Au nanocubes results in an n of 6.4 at the resonant wavelength (near-infrared) and 4.5 in off-resonant regimes (mid-infrared), unprecedented values. This method could serve as a versatile and effective approach for creating optical metamaterials with exceptionally high refractive indices.-Science journal cover design by scapiens
[Scientific Journal cover design] Low-Thermal-Budget Fluorite-Structure Ferroelectrics for Future Electronic Device Applications
In article number 2100028, Jiyoung Kim, Si Joon Kim, and their team review key factors involved in developing fluorite-structure ferroelectrics