High external-efficiency nanofocusing for lens-free near-field optical nanoscopy

About this Project

With my colleagues from UC Riverside, we develop a novel hybrid NSOM concept (Nature Photonics, 2019), which can be regarded as a combination of the merits from aperture- and apertureless-NSOM. Over all visible wavelength range, it can concentrate more than 50% of the incident light from an optical fiber to the tip of a silver nanowire (tip radius ~ 5 nm), for the study on light-matter interactions such as tip-enhanced Raman scattering (TERS, Wiki). We have demonstrated the first fiber-in-fiber-out lens-free STM-NSOM-TERS by reforming an educational STM apparatus (NaioSTM), with which 1 nm spatial resolution TERS imaging has been proven on a single-walled carbon nanotube sample. We are working on the technique transfer to other NSOM platforms, including Horiba SmartSPM and Nanonics Multiview systems.