PARTIAL-TRANSFER ABSORPTION IMAGING OF 87Rb BOSE-EINSTEIN CONDENSATES

Abstract

We present the design, testing, and implementation of a minimally-destructive, partial- transfer absorption imaging system. Partial-transfer absorption imaging in 87Rb utilizes a microwave transition to transfer a fraction of the atoms in a Bose-Einstein condensate (BEC) prepared in the F = 1 hyperfine state into the F = 2 hyperfine state, where they can be imaged on a cycling transition. The F = 1 and F = 2 hyperfine states are far apart enough in frequency that the F = 1 BEC is essentially unaffected by the imaging probe beam. The modulation transfer function, spot diagram, and point spread function for the imaging optics are simulated and measured on a bench model. We demonstrate the use of the imaging system, and we characterize the atom number and decay rate in a series of images of a repeatedly imaged BEC as a function of one of the imaging parameters, the microwave pulse time.