2015/01/31 by Markus Deiß, Björn Drews, Johannes Hecker Denschlag +3
Physics and Astronomy · #cond-mat.quant-gas #physics.atom-ph
paper · pdf · doi:10.1088/1367-2630/17/6/065019
published as New J. Phys. 17, 065019 (2015) · 22 pages, 10 figures
arxiv created 2016/12/06 · arxiv updated 2016/12/07
We study, both theoretically and experimentally, the dynamical polarizability α(ω) of \textrmRb2 molecules in the rovibrational ground state of a3Σu+. Taking all relevant excited molecular bound states into account, we compute the complex-valued polarizability α(ω) for wave numbers up to 20000 \textrmcm-1. Our calculations are compared to experimental results at 1064.5 \textrmnm (∼9400 \textrmcm-1) as well as at 830.4 \textrmnm (∼12000 \textrmcm-1). Here, we discuss the measurements at 1064.5 \textrmnm. The ultracold \textrmRb2 molecules are trapped in the lowest Bloch band of a 3D optical lattice. Their polarizability is determined by lattice modulation spectroscopy which measures the potential depth for a given light intensity. Moreover, we investigate the decay of molecules in the optical lattice, where lifetimes of more than 2 \textrms are observed. In addition, the dynamical polarizability for the X1Σg+ state is calculated. We provide simple analytical expressions that reproduce the numerical results for α(ω) for all vibrational levels of a3Σu+ as well as X1Σg+. Precise knowledge of the molecular polarizability is essential for designing experiments with ultracold molecules as lifetimes and lattice depths are key parameters. Specifically the wavelength at ∼1064 \textrmnm is of interest, since here, ultrastable high power lasers are available.