Theophilo, Klara

Date: Monday, October 10, 2016
Time: 15:00
Place: ETH Zurich, Hönggerberg, HPF G 6
Host: Jonathan Home

Atom-photon interface with fiber-tip cavities and optical tweezers

Klara Theophilo
University of Oxford, Clarendon Laboratory, Oxford, UK

The atom-photon interaction is one of the basic principles of quantum computation and communication. However, deterministic control of this interaction still one of the challenges in our field. Given that limitation, we explore the construction of a fiber-tip cavity and the development of optical tweezers. The aim is to reach the single photon/single atom regime of interaction with the capability of accessing and manipulating the quantum state of the system in a controlled manner. Our work is being developed in two different branches. The first one is the design and construction of the fiber-tip cavities, which are promising candidates for the new generation of cavity QED experiments due to their reduced size which enable a broader optical access. The other branch is the development of optical tweezers through the manipulation of an optical field with a Space Light Modulator (SLM). This system allow us to create and manipulate arrays of trapped single atoms, thus leading to the possibility of positioning and holding a single (or an array) of atoms inside our fiber-tip cavities. We have already achieved a compact fiber-tip cavity (using single mode fibers) with a finesse higher than 100 thousand for a length of approximately 100 microns. On the optical tweezers side we used the the Gerchberg-Saxton (GS) algorithm to create phase patterns in a SLM, which allowed us to construct large arrays of single trapped atoms when combined with a dipole trapping beam with wavelength of 1064nm. We have successfully achieved the single atom regime for single traps and for trap arrays as well (each trap). The single atom has a life time of the order of seconds, and the trap depth is close to 1mK. The next step is to combine the fiber-tip cavity with the atoms trapped in the dipole trap to perform cavity QED experiments. Both experiments are now working separately.