Single atoms on an optical nanofibre

We show that single atoms can be detected using a sub-wavelength-diameter silica-fibre, an optical nanofibre, and the fact that single photons spontaneously emitted from the atoms can be readily guided into a single-mode optical fibre. Moreover, we find that single atoms around the nanofibre reveal a very prominent spectral feature, that is, the excitation spectrum splits into two peaks with a very small separation, smaller than the natural linewidth.