Quantum superpositions, squeezed states and multipartite entanglement are features of the quantum world which are central for the future development of quantum information processing and metrology.

I will present simple tools and our latest observations in the experimental exploration of these phenomena with one-dimensional arrays of cold atoms coupled to the light guided by an optical nanofiber.

The sub-wavelength geometry of the nanofiber interface is also an opportunity to improve our control on how light can be scattered by several atoms. I will then give some details about our recent realisation of a switchable mirror made of a few atoms.