We examine correlations between right and left circularly polarized light for atoms in an optical lattice using a simple model. We calculate diffusion coefficients, temperatures, and discuss signatures of atomic motion in the correlations.
We present an experimental investigation of the local dynamics and spatial diffusion of atoms in a rubidium optical lattice using polarization-selective intensity correlation spectroscopy in both the time and frequency domains. Autocorrelations of the circularly polarized components of the fluorescence light are shown to give access to the atomic dynamics in a single optical potential well. By contrast, cross correlations between opposite circular components of the scattered light provide information about atomic transport in the lattice through escape and recapture between neighbor potential wells.
This paper reports studies of the optical absorption spectrum and the X-band electron spin resonance spectrum of rubidium atoms trapped in an argon matrix. The samples were formed by deposition from a mixed beam of the two constituents onto a cold plate. The optical absorption measurements showed two groups of lines. The red group, whose absorption lines are near those of the free atom, has a triplet structure; the blue group, whose absorption lines are shifted roughly 1650 ${\mathrm{cm}}^{\ensuremath{-}1}$ to the blue, has four lines. The ESR measurements showed three major trapping sites. A motorized circular polarizer was used to measure the differential absorption of right and left circularly polarized light. By monitoring the differential absorption of right and left circularly polarized light in the presence of a microwave field, a correlation was found between the optical absorption sites and the microwave absorption sites. A crystal-field model is employed in an attempt to fit the data and to understand the nature of the sites.
Birefringence in optical fibers poses a challenge to controllably delivering polarized light. Strain-induced birefringence caused by bends in the fiber, vibrations, or a large temperature gradient can significantly alter the polarization, making it particularly difficult to deliver polarization states to low-temperature environments by fiber. In this paper, we investigate the transmission of polarized light through a fiber and discuss a method we have developed for delivering arbitrarily polarized light to the base stage of a dilution refrigerator using a standard optical fiber. We have created a compact, cryogenic optical system to identify the polarization of the delivered light, while room-temperature waveplates and a mathematical fiber model are used to fully characterize and compensate for the fiber's birefringent effects. We show here that we are able to deliver horizontal, vertical, diagonal, anti-diagonal, right circular, and left circular polarization states to milli-Kelvin temperatures, with state fidelities of greater than 0.96 being achieved in all cases. Additionally, we demonstrate that we can deliver randomly selected elliptical states through a standard fiber to the refrigerator. This opens up new opportunities for fiber-based optical experiments using polarized light, such as quantum information experiments using quantum states encoded in the polarization of single photons.