Plasmonic zero mode waveguide for enhanced single molecule detection

One of the most powerful technologies for single molecule fluorescence spectroscopy at concentrations which are close to biological processes (micro and millimolar) is based on the use of Zero Mode Waveguides (ZMWs). Standard ZMWs are prepared as nanoholes array in Al thin films. Although very efficient to enable single molecule detection, Al-ZMWs are not optimized in term of fluorescence emission. On the contrary an engineered configuration where alternative metals such as Au, Ag, Al, etc. are used can produce significant enhancement in the single molecule detection. Thanks to optimized designs can be possible to enhance the fluorescence emission not only in the visible spectral range but also in the Ultraviolet (UV) and Near-infrared (NIR). Here we discuss the major results on plasmonic ZMWs and their use in single molecule fluorescence.