# Number-resolved imaging of $^{88}$Sr atoms in a long working distance optical tweezer

### Submission summary

 Authors (as Contributors): Ryan Hanley · Matthew Hill · Niamh Jackson · Matthew Jones
Submission information
Date accepted: 2020-02-07
Date submitted: 2020-02-03 01:00
Submitted by: Hill, Matthew
Submitted to: SciPost Physics
Ontological classification
Specialties:
• Atomic, Molecular and Optical Physics - Experiment
Approach: Experimental

### Abstract

We demonstrate number-resolved detection of individual strontium atoms in a long working distance low numerical aperture (NA = 0.26) tweezer. Using a camera based on single-photon counting technology, we determine the presence of an atom in the tweezer with a fidelity of 0.989(6) (and loss of 0.13(5)) within a 200 $\mu$s imaging time. Adding continuous narrow-line Sisyphus cooling yields similar fidelity, at the expense of much longer imaging times (30 ms). Under these conditions we determine whether the tweezer contains zero, one or two atoms, with a fidelity $>$0.8 in all cases with the high readout speed of the camera enabling real-time monitoring of the number of trapped atoms. Lastly we show that the fidelity can be further improved by using a pulsed cooling/imaging scheme that reduces the effect of camera dark noise.

Published as SciPost Phys. 8, 038 (2020)

### List of changes

Value of loss added to abstract