Multiprobe NSOM fluorescence

• Main Authors: Berezin Shirly, Kalanoor Basanth S., Taha Hesham, Garini Yuval, Tischler Yaakov R.
• Format: Article
• Language: English
• Published: De Gruyter 2014-04-01
• Series: Nanophotonics
• Subjects: multiprobe; nsom; spm; lumogen; fret; tuning fork probe
• Online Access: https://doi.org/10.1515/nanoph-2014-0008
• ISSN: 2192-8606; 2192-8614

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.