  We have demonstrated a new photonic structure to achieve strong optical
coupling between nanoparticle and photonic molecule by utilizing a notched
micro ring resonators. By creating a notch in the ring resonator and putting a
nanoparticle inside the notch, large spectral shifts and splittings at nm scale
can be achieved, compared to only pm scale observed by fiber tip evanescently
coupled to the surface of microsphere, thereby significantly lowered the
quality factor requirement for single nanoparticle detection. The ability for
sorting the type of nanoparticles due to very different mode shift and
splitting behavior of dielectric and metallic nanoparticles is also emphasized.
