Speaker
Description
We report on progress towards implementing Rydberg-based spin squeezing protocols [1] using small (N < 10) ensembles of Sr atoms in magic-wavelength optical tweezers. Highly-excited Rydberg states provide new ways to engineer entanglement in optical frequency standards such as Sr and Yb atomic clocks, with the first results using single atoms in tweezer arrays appearing recently [2, 3]. A similar protocol was implemented using a 1D array of ensembles of Cs atoms [4]: our current goal is to examine whether a similar approach using smaller ensembles could be used in Sr tweezer experiments.
We will describe our experiments with ensembles of 88Sr atoms trapped in long working distance optical tweezers [5] at the 813 nm magic wavelength. Our larger tweezer waist (2 microns) allows the collisional blockade to be circumvented such that we can load small ensembles into each site of a 2D reconfigurable array (site spacing ~6 microns). We demonstrate a novel technique implemented in our experiment to load spatially large (100 microns by 200 microns) 2D tweezer arrays with arbitrary atom number distributions across sites. We will present results on site-resolved spectroscopy of the 1S0-3P0 clock transition as a function of the number of atoms per tweezer site, alongside interpretation in terms of density-dependent collisions. As outlook, we intend to perform precision Rydberg spectroscopy from the 3PJ states in individual tweezers.
[1] L. I. R. Gil et al., PRL 112 (2014)
[2] G. Bornet et al., Nature 621 (2023)
[3] W. J. Eckner et al., Nature 621 (2023)
[4] J. A. Hines et al., PRL 131 (2023)
[5] N. C. Jackson et al., SciPost Phys. 8 (2020)
