Edward E. Eyler

Quantum random walk with Rydberg atoms in an optical lattice

We study the implementation of quantum random walks (QRWs) in a realistic system, an optical lattice of ultracold Rydberg atoms. The power-law nature of the dipolar interaction between Rydberg atoms influences the behaviour of QRWs. We discuss the QRW with a short-range nearest-neighbour interaction for two types of power-law interactions, the dipole-dipole and the van der Waals interaction. A specific scheme to implement a QRW using Rydberg atoms in different sites of an optical lattice is described, in which the sites are prepared using a blockade mechanism to ensure a single Rydberg atom per site.

Photoassociation of 85Rb atoms into 0u+ states near the 5S+5P atomic limits

New photoassociation data on the 0u+ levels of Rb2 below the 5S+5P1/2 limit are combined with older data (Cline et al 1994 Phys. Rev. Lett. 73 632) in a fit to potentials and spin–orbit functions. The P1/2 data exhibit oscillations in the B(v) values due to coupling between the two 0u+ series, as modelled accurately by a coupled potentials approach. The fitted value for the C3 dispersion parameter from the combined data agrees well with the value derived from the pure long-range 0g− state.

Chirp-free nanosecond laser amplifier for precision spectroscopy

We describe a simple method for greatly reducing optical phase perturbations in a nanosecond pulsed dye amplifier. The laser dye mix is tailored to produce a susceptibility near zero at the operating wavelength. Frequency shifts are reduced to less than 3 MHz, and frequency chirping to less than 10 MHz, without significant loss of amplified power. This technique has been used to improve the accuracy of precision far-UV wavelength measurements in H(2) to ~7 parts in 10(9).

Spectroscopic investigation of the A and 3 1Σ+ states of 39K85Rb.

By using a combination of molecular beam (MB) excitation spectra and two distinct ultracold molecule excitation spectra (UM+ and UM-), we have assigned high vibrational levels of the A and 3 (1)Σ(+) states from absorption spectra of the mutually strongly perturbed A (1)Σ(+) - 3 (1)Σ(+) - 1 (1)Π - 2 (3)Σ(+) - b (3)Π states of ultracold (39)K(85)Rb molecules in the energy region between 15,116 and 16,225 cm(-1) above the minimum of the ground X (1)Σ(+) state. The ultracold molecules (UM+ and UM-) are formed by radiative decay following photoassociation (PA) to a specific level of the 3(0(+)) state (UM+) or to a specific level of the 3(0(-)) state (UM-). We observe that the A and 3 (1)Σ(+) states are observable in the UM+ spectra, but absent from the UM- spectra. This is explained by considering Hunds case (c) selection rules and transition dipole moments between the upper excited A (1)Σ(+) (2(0(+))) state and the three Ω components (0(+), 0(-), and 1) at the ground-state dissociation limit. We propose further investigations of the extended potential wells of the A and 3 (1)Σ(+) states by combining short-range MB excitation spectra in a narrow Franck-Condon (FC) window near R(e) of the X (1)Σ(+) state, and long-range UM (and PA) excitation spectra, which have much larger FC windows.

Ultracold plasmas come of age

During the past decade, the availability of simple, effective methods for laser cooling and trapping has enabled enormous advances in the experimental study of atoms in their ground state. Until quite recently, however, these techniques have had much less impact on investigations of highly excited atoms and almost none on plasmas. Several laboratories have now begun experiments in which atoms are initially prepared in the ground state at submillikelvin temperatures and then excited by a laser to very high electronic states, or even ionized. The result is a gas in which the atoms are in a highly excited state but move very slowly. This unusual scenario is, in reality, quite attainable although the system is intrinsically unstable.

Generation of vacuum ultraviolet radiation for precision laser spectroscopy

We report on the generation of tunable nanosecond pulsed VUV radiation near 120 nm using difference-frequency mixing in H(2). Our scheme uses two dye lasers, one fixed at 606 nm and the other tunable in the red. These convenient wavelengths simplify the metrology needed for accurate VUV laser spectroscopy. Efficient VUV generation is attained with modest Nd:YAG pump laser energies (approximately 160 mJ at 532 nm), making the scheme attractive even when narrow bandwidths are not essential.

High-resolution saturation spectroscopy of singly-ionized iron with a pulsed UV laser

We describe the design and realization of a scheme for UV laser spectroscopy of singly-ionized iron (Fe II) with very high resolution. A buffer-gas cooled laser ablation source is used to provide a room-temperature plasma with a high density of Fe II. We combine this with a scheme for pulsed-laser saturation spectroscopy to yield sub-Doppler resolution. In a demonstration experiment, we have examined an Fe II transition near 260 nm, attaining a linewidth of about 250 MHz. The method is well suited to measure transition frequencies and hyperfine structure. It could also be used to measure small isotope shifts in isotope-enriched samples.

Rotationally-resolved depletion spectroscopy of ultracold KRb molecules

We use photoassociation of ultracold atoms to produce ultracold KRb molecules in high vibrational levels of the ground state. Depletion spectroscopy is employed to detect these molecules with both vibrational and rotational resolution.

Long-range molecular resonances in a cold Rydberg gas

We have seen spectral evidence for long-range molecular resonances involving pairs of cold Rydberg atoms. We attribute these features to avoided crossings between Rydberg-Rydberg long-range molecular interaction potentials.

The bichromatic force on small molecules

The bichromatic force is a coherent optical force that has been demonstrated to exceed the saturated radiative force from a monochromatic cw laser by orders of magnitude in atomic systems. By stimulating photon emission between two states, the bichromatic force allows us to increase the photon scattering rate beyond the spontaneous emission rate while also suppressing decays into dark states. We present studies of the efficacy of the bichromatic force on molecular systems using the test cases of B-X (0,0), P11(1.5)/ Q12(0.5) in CaF and Ã(000)−X̃(000), P11(1.5)/ Q12(0.5) in the linear triatomic molecule SrOH. Computational results from detailed multilevel models indicate that both of these molecular systems are suitable for the use of the bichromatic force, with neither repumping nor magnetic destabilization of dark states interrupting the coherent cycling at the heart of the force. We comment on the applicability of the bichromatic force to arbitrary polyatomic molecules, and present our experimental progress in demonstrating the bichromatic force on CaF and possibly on SrOH.a