Hollow Plasmonic U‐Cavities with High‐Aspect‐Ratio Nanofins Sustaining Strong Optical Vortices for Light Trapping and Sensing

Coupling of ridge hot spots with a scalable resonant U-cavity fully traps light in intense optical vortices, generating strong and sharp resonances with widths as small as 14 nm. Tunable resonance wavelengths from visible to near-infrared are achieved by controlling the cavity dimensions. Sensing performance with a figure of merit of 136 is attained and biosensing in a protein-ligand scheme is demonstrated. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.