Hironobu HORI, Keiko TAWA^*, Kenji KINTAKA¹, Junji NISHII¹, and Yoshiro TATSU

Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka 563-8577, Japan
¹Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka 563-8577, Japan

(Received July 15, 2008; Accepted November 26, 2008)

The fluorescence intensity of a sample placed on a metal grating pattern is enhanced due to excitation by the electric field of the grating-coupled surface plasmon resonance (GC-SPR). The dependence of the enhancement on groove depth and surface profile was studied with the aim of improving the sensitivity of fluorescence detection. The enhancement was found to depend on the groove depth, with intensity most enhanced on grating substrate of about 20 nm depth, which produced an intensity about 30 times greater than that on a flat borosilicate glass substrate. Rigorous coupled wave analysis calculation showed that the shape of the groove influenced GC-SPR, suggesting that controlling not only the depth but also the shape of the grating surface profile can be an important factor in improving the sensitivity of detection by fluorescence microscopy.

Key words: fluorescence, microscopy, surface plasmon resonance, grating structure, sensitivity of fluorescence detection

^*E-mail address: tawa-keiko@aist.go.jp