Minimal Overhead Detection of ¹⁷¹Yb⁺ Micromotion in 3D

Atomic ions stored in RF Paul traps exhibit driven motion at the trap frequency known as micromotion [1]. This modulates optical fields seen by the ions, presenting a nuisance for their use in metrology and quantum information [2,3,4]. In heavier ions, the cooling linewidth and trap frequency are often commensurate, complicating measurement of the induced sidebands. In Yb⁺, the standard 935 nm repump transition has a natural linewidth of 2π×4.2 MHz in comparison to the cooling linewidth of 2π×19.6 MHz and standard trapping frequencies of Ω_RF~2π×30 MHz, allowing resolution of the micromotion spectrum without inducing Doppler heating. In-line fiber EOM permits rapid laser control allowing easy measurement along three directions without increasing detection background scatter or inducing trap charging. The result is a rapid method for probing and minimizing micromotion in 3D with very low operational overhead. 

[1] D. J. Berkeland (1998) 10.1063/1.367318

[2] J. Keller (2015) 10.1063/1.4930037

[3] S. M. Brewer (2019) 10.1103/PhysRevLett.123.033201

[4] J. P. Gaebler (2016) 10.1103/PhysRevLett.117.060505