K. Richard Overstreet

Cold Cs Rydberg-gas interactions

We present calculations of potential curves for very high-n (89D) Cs Rydberg-atom pairs, including a background electric field. From these potentials, we show that energy transfer occurs at rates of {approx}30-70 MHz, background electric fields play an important role and dipole-dipole- and quadrupole-quadrupole-induced avoided curve crossings should lead to conversion of electronic to kinetic energy, n-changing collisions, and observable ultracold long-range Rydberg molecules.

Stark slowing asymmetric rotors: weak-field-seeking states and nonadiabatic transitions.

Stark deceleration is one of the few methods that can be used to slow polyatomic molecules. We present calculations of Stark shift energies, a quantitative analysis of nonadiabatic transition probabilities, and orientational distribution functions applicable to typical Stark slowing conditions for the two small asymmetric rotors nitromethane and acetaldehyde. We show that asymmetric polyatomic molecules are good candidates for Stark slowing.

Analysis of long-range Cs Rydberg potential wells

We analyse bound states at long-range (R∼5 μm) for pairs of Cs atoms in the 89D and neighbouring states. These wells are due solely to avoided crossings between the van der Waals pair interaction potentials. The depth of the wells is ∼40 MHz, and vibrational spectra consist of hundreds of bound states. We present detailed calculations of the properties of two of these wells at different electric fields (∼ mV cm− 1), since the electric field changes the well depth and shape. We estimate bound-state lifetimes μs, lineshapes, and two-photon excitation and detection rates ∼Hz from the 6P state at a temperature of T = 40 μK for these molecules.

Tunable four-pass narrow spectral bandwidth amplifier for use at ∼508 nm

We report the implementation of a tunable, narrow-spectral-bandwidth, pulsed, four-pass dye-laser amplifier with strongly reduced amplified spontaneous emission. We present temporal pulse profiles, pulse spectra, and gain measurements of the amplifier output for the case of Coumarin 307 dye as the gain medium, seeded at wavelengths of ∼508 nm and pumped at 355 nm.

Long Range Cs Rydberg Molecules

We present calculations of long range Cs Rydberg molecules. The molecules are formed by multipole interactions and can be controlled using an external electric field. Experimental progress on detecting these molecules will be reviewed.

Long Range Interactions and Inelastic Collisions in a Cold Cs Rydberg Gas

Studies of cold Cs Rydberg atom elastic and inelastic collisions will be presented. Elastic collisions are investigated by observing spectral line broadening and shifts. Inelastic collisions are examined by measuring photofragment angle and velocity distributions.