Cavity probe for real-time detection of atom dynamics in an optical lattice

Robert D. Niederriter, Chandler Schlupf, Paul Hamilton

Abstract

We propose and demonstrate real-time sub-wavelength cavity QED measurements of the spatial distribution of atoms in an optical lattice. Atoms initially confined in one "trap" standing wave of an optical cavity mode are probed with a second "probe" standing wave. With frequencies offset by one free spectral range, the nodes of the trap fall on the anti-nodes of the probe in the 10 lattice sites around the center of the cavity. This lattice site independent atom-cavity coupling enables high sensitivity detection of atom dynamics even with atoms spread over many lattice sites. To demonstrate, we measure the temperature of 20-70 K atom ensembles in 10 s by monitoring their expansion of 100 nm after sudden release from the trap lattice. Atom-cavity coupling imprints the atom dynamics on the probe transmission. The new technique will enable improved non-destructive detection of Bloch oscillations and other atom dynamics in optical lattices.