3part 

Interesting properties and
applications
Sub-wavelength control of light: could be used
in ultra high resolution spectroscopy and
super high density optical data storage
Surface enhanced Raman scattering can be
used to produce optical sensors, with single
molecule resolution
Surface enhanced fluorescence is used in
biological imaging
Extremely low threshold for nonlinear effects,
very high Q-factors
Quantum effects can be important in some
conditions