Collision spectroscopy with optically prepared atoms

M. Allegrini

N. Andersen

The possibility of optical target preparation has added new dimensions to atomic collision spectroscopy. By suitable choices of photon wavelength and polarization, the shape and dynamics of the target atom can be controlled and manipulated before the interaction with the projectile. Similarly, the shape and dynamics of the atomic states in the exit channel can be monitored by polarization analysis of the photons emitted in the subsequent optical decay. Finally, the target temperature may be strongly reduced by laser cooling and used for recoil ion momentum spectroscopy. A series of simple examples are presented in order to demonstrate the kind of insight into the interaction dynamics that may be gleaned from combined experimental and theoretical studies of this kind.

R V Brooks, Alexander Guttridge, Matthew D. Frye +4 more

Abstract We prepare pairs of 133Cs atoms in a single optical tweezer and perform Feshbach spectroscopy for collisions of atoms in the states (f = 3, m f = ±3). We detect enhancements in pair loss using a detection scheme where the optical tweezers are repeatedly subdivided. For atoms in the state (3, −3), we identify resonant features by performing inelastic loss spectroscopy. We carry out coupled-channel scattering calculations and show that at typical experimental temperatures the loss features are mostly centred on zeroes in the scattering length, rather than resonance centres. We measure the number of atoms remaining after a collision, elucidating how the different loss processes are influenced by the tweezer depth. These measurements probe the energy released during an inelastic collision, and thus give information on the states of the collision products. We also identify resonances with atom pairs prepared in the absolute ground state (f = 3, m f = 3), where two-body radiative loss is engineered by an excitation laser blue-detuned from the Cs D2 line. These results demonstrate optical tweezers to be a versatile tool to study two-body collisions with number-resolved detection sensitivity.

James Veale

Y. Yamazaki

Recently, a new project, ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons), has started, which aims at studying collision dynamics with slow antiprotons and high precision spectroscopy of antiprotonic atoms. It is expected that the ultra slow monoenergetic antiproton beams will open a new physics regime relating to antimatter science under very well controlled conditions. In the present report, several research plans, which includes ionization, excitation, stopping power, channeling, antiprotonic atom formation, high resolution antiprotonic atom spectroscopy, etc. are discussed. The way to prepare ultra slow antiprotons is also presented.

Daniel Kleppner