We have measured the radiative lifetimes of S, P, and D states of rubidium in the range 30 <=n <=50 using cold atoms in a MOT. Two experimental techniques have been adopted to reduce random and systematic errors. First, a frequency doubled, pulse amplified diode laser is used to excite the target nl Rydberg state. The output from this laser has a Fourier-transform linewidth of 100 MHz at 480 nm, and results in minimal shot-to-shot variation in the Rydberg state population when it is used to drive the 5p3/2 -> nl transition. Second, we monitor the target state population as a function of time delay from the 480 nm laser pulse using a short mm-wave pulse that is resonant with the two-photon transition nl -> (n+1)l. We then selectively field ionize the (n+1)l state, and detect the resulting electrons with a microchannel plate (MCP). We step the time delay between the laser pulse and the mm-wave pulse and acquire the MCP signal as a function of the delay. This signal is an accurate mirror of the nl population, which we fit to an exponential decay to recover the nl state lifetime.
APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts
- Pub Date:
- June 2007