Off-resonant Fano-enhanced single-molecule-resolution imaging with a CW source
Nanoscale, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1039/d6nr02277d
- Dergi Adı: Nanoscale
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, EMBASE, INSPEC, MEDLINE
- Akdeniz Üniversitesi Adresli: Evet
Özet
Apertureless scanning near-field optical microscopy (a-SNOM) is typically limited to ∼10 nm resolution by the tip apex size. We numerically demonstrate that ∼1 nm resolution can be achieved under continuous-wave (CW) illumination by exploiting Fano path interference. A defect center that naturally forms at the apex of a metal-coated AFM tip acts as a quantum object and induces Fano interference, forcing a stronger but normally off-resonant plasmonic mode (597 nm) to operate effectively on resonance at the driving wavelength (520 nm). Because this interference occurs only beneath the defect, an ∼1 nm wide defect-dependent contribution is formed inside the broader apex hotspot; the full metallic hotspot is not reduced to 1 nm. Using this off-resonant Fano-enhanced field, we numerically resolve two closely spaced model objects based on exact three-dimensional Maxwell simulations.