2015/02/03 by Zhendong Zhu, Zhu, Zhendong, Benfeng Bai +7
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Gold and Silver Nanoparticles Synthesis and Applications #Optics (physics.optics) #Orbital Angular Momentum in Optics #Plasmonic and Surface Plasmon Research
paper · pdf · doi:10.48550/arxiv.1502.00753
openalex publication_date 2015/02/03 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28
Cascaded optical field enhancement (CFE) can be realized in some specially designed multiscale plasmonic nanostructures, where the generation of extremely strong field at nanoscale volume is crucial for many applications, for example, surface enhanced Raman spectroscopy (SERS). Here, we propose a strategy of realizing a high-quality plasmonic nanoparticle-in-cavity (PIC) nanoantenna array, where strong coupling between a nanoparticle dark mode with a high order nanocavity bright mode can produce Fano resonance at a target wavelength. The Fano resonance can effectively boost the CFE in the PIC, with a field enhancement factor up to 5X102. A cost-effective and reliable nanofabrication method is developed with room temperature nanoimprinting lithography to manufacture high-quality PIC arrays. This technique guarantees the generation of only one gold nanoparticle at the bottom of each nanocavity, which is crucial for the generation of the expected CFE. As a demonstration of the performance and application of the PIC array, it is used as active SERS substrate for detecting 4-aminothiophenol molecules. The SERS enhancement factor up to 2X107 is obtained experimentally, verifying the field enhancement and potential of this device.