Cecilia Muldoon

Control and manipulation of cold atoms in optical tweezers

Neutral atoms trapped by laser light are among the most promising candidates for storing and processing information in a quantum computer or simulator. The application certainly calls for a scalable and flexible scheme for addressing and manipulating the atoms. We have now made this a reality by implementing a fast and versatile method to dynamically control the position of neutral atoms trapped in optical tweezers. The tweezers result from a spatial light modulator (SLM) controlling and shaping a large number of optical dipole-force traps. Trapped atoms adapt to any change in the potential landscape, such that one can rearrange and randomly access individual sites within atom-trap arrays.

Spatial light modulators for the manipulation of individual atoms

We propose a versatile arrangement for the trapping and manipulation of single atoms in optical tweezers formed by the direct image of a spatial light modulator (SLM). The scheme incorporates a high numerical aperture microscope to map the intensity distribution of a SLM onto a cloud of cold atoms. The regions of high intensity act as optical dipole-force traps. With a SLM fast enough to modify the trapping potential in real time, this technique is well suited for the controlled addressing and manipulation of arbitrarily selected atoms.

Coherent imaging of extended objects

When used with coherent light, optical imaging systems are inherently unable to reproduce both the amplitude and the phase of a two-dimensional field distribution. This is because their impulse response function varies slowly from point to point, a property known as non-isoplanatism. For sufficiently small objects, this usually results in a phase distortion and has no impact on the measured intensity. Here, we show that the intensity distribution can be dramatically distorted when extended objects are imaged. We illustrate the problem using two simple examples: the pinhole camera and the thin lens. The effects predicted by our theoretical analysis are confirmed by experimental observations.

Optical tweezers for manipulating single atoms

Our goal is to realize a scalable cluster of entangled atoms trapped in fully controllable arrays of optical tweezers. This relies on the ability to manipulate, address and couple individual entities, using either cavity-mediated techniques or controlled collisions. Such a network of entangled atoms would provide the resources needed for one-way quantum computing [1].

Towards a scalable dipole-trapping scheme for neutral atoms

We present a new scheme for trapping single atoms in separate dipole-traps and manipulating them individually. It relies on a spatial light-modulator to create the traps and will find applications in cavity-QED.