Evanescent optical fluorescence excitation: the role of photonic mode density

• Presented at: Conference on Micro (MEMS) and Nanotechnologies for Defense and Security, Orlando, April 10-12, 2007
• Published in: Proceedings of the society of photo-optical instrumentation engineers (SPIE), vol. 6556, p. 65560G
• : SPIE-INT SOC OPTICAL ENGINEERING, 2007

In this paper we will discuss a few basic concepts concerning the use of evanescent optical fields for the excitation of fluorescent chromophores placed near the interface. The observation of enhanced fluorescence from chromophores excited by surface plasmon and waveguide modes will be presented and discussed. We attribute the enhancement to the near-field interaction between the chromophores and the increased photonic mode density by surface plasmon and waveguide modes. We determined limits of detection (LOD) of DNA hybridisation using the same sensor architecture by surface plasmon fluorescence spectroscopy (SPFS) and optical waveguide fluorescence spectroscopy (OWFS). Both SPFS and OWFS techniques have the same detection principle using an enhanced electromagnetic field to excite fluorophores and make it possible to monitor DNA hybridisation in real-time with high sensitivity. The relative photonic mode density of each mode was calculated under the resonance condition, and these values are reflected in the LOD values.

Keywords: evanescent optics ; surface plasmon ; waveguide modes ; photonic mode density ; fluorescence

Reference

• LOB-CONF-2010-001

Record created on 2010-02-17, modified on 2017-05-10