Journal ArticleProtein sensing using deep subwavelength-engineered photonic crystalsZhang, Yanrong; Whittington, Christopher; Layouni, Rabeb; Cotto, Andres; Arnold, Kellen; Halimi, Sami; Weiss, SharonWe demonstrate higher sensitivity detection of proteins in a photonic crystal platform by including a deep subwavelength feature in the unit cell that locally increases the energy density of light. Through both simulations and experiments, the sensing capability of a deep subwavelength-engineered silicon antislot photonic crystal nanobeam (PhCNB) cavity is compared to that of a traditional PhCNB cavity. The redistribution and local enhancement of the energy density by the 50 nm antislot enables stronger light-molecule interaction at the surface of the antislot and leads to a larger resonance shift upon protein binding. This surface-based energy enhancement is confirmed by experiments demonstrating a nearly 50% larger resonance shift upon attachment of streptavidin molecules to biotin-functionalized antislot PhCNB cavities.Optica2023-12-0510481245Optics Letters0146-9592https://doi.org/10.1364/OL.5105411852157; 2244050National Science Foundation