Protein sensing using deep subwavelength-engineered photonic crystals

• Published in: Optics letters Vol. 49; no. 2; p. 395
• Main Authors: Zhang, Yanrong, Whittington, Christopher S, Layouni, Rabeb, Cotto, Andres M, Arnold, Kellen P, Halimi, Sami I, Weiss, Sharon M
• Format: Journal Article
• Language: English
• Published: United States 15-01-2024
• Subjects: Photons; Silicon
• ISSN: 1539-4794
• DOI: 10.1364/OL.510541

We demonstrate a 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 enable stronger light-molecule interaction at the surface of the antislot and lead 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.