Broadband measurement of Feibelman's quantum surface response functions.

ABSTRACT: Feibelman [Formula: see text]-parameter, a mesoscopic complement to the local bulk permittivity, describes quantum optical surface responses for interfaces, including nonlocality, spill-in and -out, and surface-enabled Landau damping. It has been incorporated into the macroscopic Maxwellian framework for convenient modeling and understanding of nanoscale electromagnetic phenomena, calling for the compilation of a [Formula: see text]-parameter database for interfaces of interest in nano-optics. However, accurate first-principles calculations of [Formula: see text]-parameters face computational challenges, whereas existing measurements of [Formula: see text]-parameters are scarce and restricted to narrow spectral windows. We demonstrate a general broadband ellipsometric approach to measure [

SUBMITTER: Chen Z 

PROVIDER: S-EPMC12167949 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature