Nanobridges formed through electron beam image reversal lithography for plasmonic mid-infrared resonators with high aspect ratio nanogaps.

We present the emergence of nanobridge networks through a nanofabrication technique based on image-reversal electron beam lithography and demonstrate plasmonic structures with high aspect ratio sub-20 nm gaps capable of strong intensity enhancement in the mid-infrared range. The proposed technique, which employs the engineering of natural formations of nanobridges in predefined templates, could serve as an alternative path for realizing mid-infrared plasmonic resonators with potential applications in surface plasmon polariton-based integrated optics, and enhancement of light-matter interaction for high efficiency photodetection and nanoscale light emitters.