Multiprobe NSOM fluorescence

In this paper, we demonstrate simultaneous AFM/NSOM using a dual‐tip normal tuning‐fork based scanning probe microscope. By scanning two SPM probes simultaneously, one dedicated for AFM with a standard tip diameter of 20 nm, and the second having a 150 nm aperture NSOM fiber with 200 nm thick gold coating, we combine the benefits of ∼20 nm spatial resolution from the AFM tip with the spectral information of a near‐field optical probe. The combination of simultaneous dual‐tip scanning enables us to decouple the requirements for high resolution topography and probe functionality. Our method represents a marked shift from previous applications of multi‐probe SPM where essentially a pump‐probe methodology is implemented in which one tip scans the area around the second. As a model system, we apply dual‐tip AFM/NSOM scanning to a sample of spin‐cast nano‐clustered Lumogen dyes, which show remarkable brightness and photochemical stability. We observe morphology features with a resolution of 20 nm, and a near‐field optical resolution of 150 nm, validating our approach.