The strong light-matter interaction that occurs between a single dye molecule and a plasmonic nanoantenna has attracted tremendous attention due to the resulting strong fluorescence enhancement, which can improve the resolution of single molecule imaging. These plasmonic nanoantennas are metal nanoparticles that transfer free-space, far-field radiation to localized electromagnetic energy. Besides the fluorescence enhancement, we have discovered that the far-field emission pattern of a dye molecule is also largely modified when coupled to plasmonic nanoantennas. In particular, using single-molecule microscopy, we have measured a large difference in the emission polarization from single Cy5.5 molecules upon coupling to a plasmonic gold nanorod. To our knowledge, this is the first study that shows deliberate tuning of the emission polarization of single molecules via nanoantenna coupling. This study will improve high-sensitivity single-molecule fluorescence imaging by increasing the tunability and control of plasmon-enhanced fluorescence, and it will further provide an <i>in situ</i> probe for measuring—and controlling—light-matter interactions on the nanometer scale.

Single-molecule fluorescence sheds light on coupled dye-nanoparticle systems

255th National Meeting (2018)

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