Congratulations to Xin, Megan, Brett, Kelsey, and Haoran, who successfully trapped strontium in a magneto-optical trap for the first time on Monday evening, making the center of our UHV chamber the second* coldest place in Wisconsin! In the picture below, the glowing blue ball at the center of the round vacuum window is a cloud of strontium-88 atoms cooled to ~1/1000th of a degree above absolute zero using laser cooling, and held levitating in place by a combination of laser light and large magnetic field gradients.

This represents a major milestone along the way towards our goal of building a new kind of optical lattice atomic clock that we will use to perform tests of fundamental physics, develop new applications of ultra-precise optical clocks, and explore novel ways to further enhance the performance of these remarkable instruments.

 

*In case you’re wondering, the coldest place in Wisconsin is currently right down the hall from us in Mark Saffman’s labs, where his rubidium and cesium atoms are laser-cooled to even lower temperatures. But we’re hot (or is it cold…?) on their heals, and will most likely overtake them as the record holders once we implement a second stage of narrow-line laser cooling. We can also hold our heads high and stake our place in history as the first group to laser cool and trap strontium atoms (or for that matter any alkaline-earth or alkaline-earth-like atom) in Wisconsin.