Atom-light Quantum Interface Based on Nanofiber Traps

8 10/2014

Wednesday, 08 Oct. 2014, 10:00 - 12:00

Workgroup Zeilinger Group

Presenter: Eva Bookjans
Host: Anton Zeilinger
Where: IQOQI Kitchen, 3rd Floor, Boltzmanngasse 3, 1090 Vienna

The strong coupling between the guided mode of a tapered optical nanofiber with sub-wavelength diameter and atoms close to the fiber surface make it an ideal system for implementing an efficient atom-light quantum interface. Recently, significant progress has been made in manipulating and detecting cold atoms trapped in a 1-D optical lattice created by the evanescent field of a tapered optical nanofiber [1-3]. The one-dimensional geometry is well suited for a range of applications, such as the realization of a quantum simulator or sensing applications. Together with the mature technology of interconnecting optical fibers, atomic ensembles trapped around nanofibers have additionally the potential of playing an integral part in the construction of complex quantum networks. Atoms trapped around a nanofiber could, for example, serve as a quantum memory, which is readily linked to other types of quantum systems by photons guided through the fiber mode.

We report on the preparation and detection of an atom number distribution in a one-dimensional atomic lattice with the variance -14dB below the Poissionian noise level in an atom-nanofiber system [4]. The atom number is measured through dual-color homodyne interferometry with a pW-power shot noise limited probe [5-7]

Strong coupling of the evanescent probe guided by the nano-fiber allows for a real-time measurement with a precision of ±8 atoms on an ensemble of some 103 atoms in a one-dimensional trap. The method is very well suited for generating collective atomic entangled or spin-squeezed states via a quantum non-demolition measurement as well as for tomography of exotic atomic states in a one-dimensional lattice.