Robust Optical Sculpting For Manipulating Ultracold Atoms

Gediminas Juzeliūnas, Patrik Öhberg

Benjamin L. Brown, Ian A. Walmsley

Coherent femtosecond optical pulses provide a unique means to manipulate the collision process between a pair of ultracold atoms. The capability to arbitrarily shape strong electric fields gives the possibility of dynamically sculpting the system Hamiltonian on the collisional timescale. In this paper we explore theoretically physically intuitive excitation schemes by which a control field can manipulate the vibronic state populations in an ultracold molecular system, with the goal of bringing atom pairs to short ( R < 10 Å) separations where they may form a tightly bound molecule. The microscopic dynamics of individual pairs of colliding atoms under the influence of an external optical field are explored through explicitly time-dependent numerical simulations. The results provide physical justification for the employment of optimal control techniques for the achievement of state-selective formation of ultracold molecules.

Halina H. Rubinsztein-Dunlop

Sculpted light refers to the generation of custom designed light fields. These light fileds can be applied in many diverse fields ranging from interrogating single atoms or atom assembly to using these fields for optical micromanipulation and optical tweezers as well as creating new quantum devices and sensors. We consider here the study and application of light with structured intensity, polarization and phase. We can create custom fields in multiple planes using dynamic and geometric phase control. As an example, the use of sculpted light in imaging has led to superresolution microscopy developed by Betzig, Hell and Moerner (2014 Nobel prize in Chemistry). Sculpted light can be generated using several technologies. These are spatial light modulators (SLM) and Digital Micromirror Devices (DMD) that enable the production of configurable and flexible confining potentials at the nano and micron-scale. Sculpted light can also be produced using time averaged methods such as Acousto-Optics Modulators (AOM), enabling production of highly configurable time-averaged traps. All these methods achieve dynamical and flexible sculpted light fields and enable imaging of the amplitude patterns, phase and polarization. Using these sculpted light we can produce novel optical potentials which can be used for intricate studies of light -matter interactions in a variety of environments. We will describe their use ranging from studies such as quantum thermodynamics using ultra cold atoms to trapping and manipulating nano and micron-size objects or even making measurements in-vivo inside biological cells.

Renzo Testa, Donatella Cassettari

Precise and flexible manipulation of the motional state of ultracold atoms is a fundamental enabling technology for diverse applications such as quantum sensing and quantum computation. In this paper we propose a general, simple and highly efficient method to engineer the motional state of a Bose-Einstein condensate with time-dependent optical fields, which can be realized experimentally with existing light sculpting techniques. We demonstrate numerically how to engineer superpositions of persistent currents in a toroidal trap, achieving very high fidelity. We also study in detail the stability of the state over time, and we present an analytical two-state model that approximates well the evolution of the state in presence of self-interactions.

Gyu-Boong Jo

Nathan E. Lundblad