Abstract
We perform fluorescence imaging of a single 87Rb atom after its release from an optical dipole trap. The time-of-flight expansion of the atomic spatial density distribution is observed by accumulating many single atom images. The position of the atom is revealed with a spatial resolution close to 1 μm by a single-photon event, induced by a short resonant probe. The expansion yields a measure of the temperature of a single atom, which is in very good agreement with the value obtained by an independent measurement based on a release-and-recapture method. The analysis presented in this paper provides a way of calibrating an imaging system useful for experimental studies involving a few atoms confined in a dipole trap.
Highlights
Experimental setupOur experimental setup has been described elsewhere [9] and is summarized in figure 1
The analysis of the time-of-flight of a single atom released from our microscopic dipole trap serves as a calibration of our imaging system
We use the same lens to collect the fluorescence light, which is sent onto an avalanche photodiode (APD) and an image intensifier4 followed by a low-noise CCD camera5
Summary
Our experimental setup has been described elsewhere [9] and is summarized in figure 1. A single 87Rb atom is trapped in a tight optical dipole trap. The dipole trap is produced by focusing a laser beam (λtrap = 850 nm) down to a spot with waist w0 = 1.1 μm, using a high numerical aperture aspheric lens (NA = 0.5). The trap depth can be as large as 20 mK for a laser power of 80 mW. In order to image the atom, we illuminate it with probe light, which consists of two counterpropagating beams (to avoid radiation pressure force) in a σ+–σ− configuration, and is resonant with the (5 2S1/2, F = 2) to (5 2P3/2, F = 3) transition. We superimpose repumping light on the probe beams, tuned to the (5 2S1/2, F = 1) to (5 2P3/2, F = 2) transition
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
