"[2] The zero-mode waveguide is made possible by creating circular or rectangular nanoapertures using focused ion beam on an aluminium layer.
[3] The zero-mode waveguide can also enhance fluorescence signals due to surface plasmons generated at metal-dielectric interfaces.
[4] Due to surface plasmon generation field is localized and enhanced as well as it changes the LDOS inside the cavity which leads to increase in Purcell Factor of analyte molecules inside the zero-mode waveguide[5] The zero-mode waveguide is very useful for Ultraviolet Auto-fluorescence spectroscopy on tryptophan-carrying proteins like beta-galactosidase.
[6] With further modification of the zero-mode waveguide with a conical reflector, it is possible to study the dynamic process of smaller proteins like streptavidin with 24 tryptophan.
,[7] The modified zero-mode waveguide with a conical reflector can be further optimized to enhance the signal-to-noise ratio and reach the ultimate sensitivity of single tryptophan proteins like TNase.