Surface plasmon coupled nano-probe for near field scanning optical microscopy

• Published in: Optics express 2020-05, Vol.28 (10), p.14831-14838
• Main Authors: Yin, Xiaojin, Shi, Peng, Yang, Aiping, Du, Luping, Yuan, Xiaocong
• Format: Article
• Language: English
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.389176

Near-field scanning optical microscopy (NSOM) is a powerful tool for study of the nanoscale information of objects by measuring their near-field electric field distributions. The near-field probe, which determines NSOM system performance, can be either a scattering-type or an aperture-type. Both types have strengths and weaknesses. Here we propose and study a surface plasmon-coupled type nano-probe, which works as a hybrid scheme and could potentially combine the advantages of the two NSOM probe types. The key element of the proposed probe is a nanoparticle-on-film structure designed on a tapered fiber tip. On the one hand, the probe can yield the signals scattered in the near field by a nanoparticle with a scattering mechanism; on the other hand, the scattered signals can be transmitted by the metal film and coupled into the fiber via surface plasmon coupled emission, thus providing a collection mode similar to an aperture-type NSOM. This will lead to signal enhancement, while greatly suppressing background noise. This surface plasmon-coupled nano-probe thus has great potential for near-field optical microscopy applications.