Progress towards isotope-dependent trapping of strontium*

Independently controllable trapping potentials for different atomic elements, isotopes, and states are useful for forming quantum degenerate gases through sympathetic cooling, for quantum computing architectures\footnote{Anderlini et al., Nature 448, 452-456 (2007)}, and for fundamental studies in many-body physics\footnote{Mandel et al., Phys. Rev. Lett. 91, 010407 (2003)}. In strontium, the large isotope shifts ($\sim100$ MHz) relative to the narrow \textsuperscript{1}S\textsubscript{0}-\textsuperscript{3}P\textsubscript{1} intercombination line (7.5 kHz) offers the possibility of creating multi-isotope optical traps in which the potentials are optimized for each individual species, such as \textsuperscript{86}Sr with \textsuperscript{87}Sr or \textsuperscript{86}Sr with \textsuperscript{88}Sr, allowing for efficient evaporative cooling. We will present results for confinement of \textsuperscript{84}Sr when a dimple is created using far-detuned 689 nm light ($\Gamma/\Delta \sim 10^{-5}$) within a large-volume 1064 nm dipole trap ($\Gamma/\Delta \sim 10^{-7}$). The 689 nm dimple will be used to develop a trap for efficient creation of \textsuperscript{88}Sr Bose-Einstein condensates, overcoming the slow evaporation currently required.