Iain Chan

Measurement of excited-state lifetime using two-pulse photon echoes in rubidium vapor

We report a measurement of the 5P3/2 excited-state lifetime using two-pulse photon echoes in Rb vapor. The measurement is precise to ∼1% and agrees with the best measurement of atomic lifetime in Rb. The results suggest that a measurement precise to ∼0.25% is possible through additional data acquisition and study of systematic effects. The experiment relies on short optical pulses generated from a cw laser using acousto-optic modulators. The excitation pulses are on resonance with the F=3-->F′=4 transition in Rb85 or the F=2-->F′=3 transition in Rb87. The resulting photon echo signal is detected using a heterodyne detection technique. The excited-state lifetime is determined by measuring the exponential decay of the echo intensity as a function of the time between the excitation pulses. We also present a study of the echo intensity as a function of excitation pulse area and compare the results to simulations based on optical Bloch equations. The simulations include the effects of spontaneous emission as well as spatial and temporal variations of the intensities of excitation pulses.

Precise determination of atomic g-factor ratios from a dual isotope magneto-optical trap

We demonstrate a technique, for carrying out precise measurements of atomic g-factor ratios, which relies on measurements of Larmor oscillations from coherences between magnetic sublevels in the ground states of {sup 85}Rb and {sup 87}Rb atoms confined in a dual isotope magneto-optical trap. We show that a measurement of g{sub F}{sup (87)}/g{sub F}{sup (85)} with a resolution of 0.69 parts per 10{sup 6} is possible by recording the ratio of Larmor frequencies in the presence of a constant magnetic field. This represents the most precise single measurement of g{sub F}{sup (87)}/g{sub F}{sup (85)} without correcting for systematic effects.

Time-Domain Interferometry with Laser-Cooled Atoms

Abstract A single-state grating echo interferometer offers unique advantages for time-domain studies of light–matter interactions using laser-cooled atoms, including applications that involve precision measurements of atomic recoil, rotation, and gravitational acceleration. To illustrate the underlying physics, we first discuss the output signal of the interferometer in the absence of spontaneous emission. The influence of spontaneous emission, magnetic sublevels, and the spatial profile of excitations beams on matter wave interference in a two-pulse interferometer is described, followed by a discussion of transit time limited experiments using a multipulse technique that offers several advantages. We also examine the enhancement in signal size achieved by a lattice interferometer. The sensitivity of the interferometer to magnetic gradients and gravitational acceleration is discussed along with extensions to frequency-domain studies of atomic recoil and rotation. Applications of coherent transient effects and echo techniques associated with internal state labeled interferometers that utilize magnetic sublevels of a single hyperfine state are considered for precise measurements of magnetic interactions such as atomic g-factor ratios. The article concludes with an overview of the suitability of the traditional two-pulse photon echo technique for measurements of atomic lifetimes and studies of superradiant emission in laser-cooled samples.

Progress toward a precision measurement of the atomic recoil frequency using an echo-type atom interferometer

We discuss progress towards a precision measurement of the atomic recoil frequency in 85Rb using an echo-type atom interferometer. We report a single measurement precision of ~ 300 ppb on a timescale of ~ 50 ms.