New paper on tracking single atoms in a thermal ensemble without laser cooling December 2022

We have isolated and tracked very slowly moving individual atoms without the aid of laser cooling. Passive filtering enabled us to carefully select atoms whose three-dimensional velocity vector has a magnitude below v¯/20, where v¯ is the mean velocity of the ensemble. Using a novel photon correlation technique, we could follow the three-dimensional trajectory of single, slowly moving atoms for >1μs within a 25μm field of view, with no obvious limit to the tracking ability while simultaneously observing Rabi oscillations of these single emitters. Our results demonstrate the power and scalability of thermal ensembles for utilization in quantum memories, imaging, and other quantum information applications through bottom-up approaches.

Selecting and measuring single slow atoms. (a) Schematic of the experiment. Atoms from the silicon collimator are first pumped into F = 1 and then selectively pumped back to F = 2. A Doppler-free probe beam is used to detect the selected atoms. The angle between repump and the
atomic beam is θ =47 ◦. Two cleaved fiber tips are placed on the image plane of the imaging system with a numerical aperture (NA) of 0.42. (b) The involved energy levels. The repump is detuned by ∆ to select a certain group of atoms. (c) The raw coincidences with different time delays from two
SPCMs at ∆ = −80 MHz, corresponding to a velocity of v ≈ 100m/s.

New PhDs!

I’m very privileged to participate in the Ph.D.s hooding ceremony today for Raman Lab member Di Lao.  Later this month we’ll celebrate Chao Li as well, who is defending.  Congrats to these two fine scientists!