Sanggon Kim, Ning Yu, Xuezhi Ma, Yangzhi Zhu, Qiushi Liu, Ming Liu & Ruoxue Yan
Researchers from the University of California demonstrated a two-step sequential nanofocusing technique to achieve high-efficiency, broadband and dual-directional nanofocusing for near-field optical excitation and spectrum collection. They achieved an external nanofocusing efficiency of ~50% over nearly all the visible range on a fibre-coupled nanowire scanning probe, which is capable of both light delivery and spectrum collection with nanoscale spatial resolution. By integrating this with a NaioSTM they were able to demonstrate lens-free tip-enhanced Raman spectroscopy and achieved 1 nm spatial resolution. The high performance and vast versatility offered by this fibre-based nanofocusing technique allow for the easy incorporation of nano-optical microscopy into various existing measurement platforms.
Their work was published in Nature Photonics (2019).