Single Trapped 171Yb+ for Optical Frequency Standards

An optical clock or frequency standard based on the interrogation of an atomic transition in the optical domain, operates at ~10
¹⁴
Hz is capable of providing orders of magnitude better accuracy than the present primary standard of frequency or time operating in the microwave range. Optical transitions of an ions, confined within a radio frequency ion trap and laser cooled to ~mK temperature, provides better long term stability since they are free from Coulomb and intra-atomic interactions. Optical frequency standards have been realized with several ions, e.g.,
¹⁹⁹
Hg
⁺
,
¹⁷¹
Yb
⁺
,
¹¹⁵
In
⁺
,
⁸⁸
Sr
⁺
,
⁴⁰
Ca
⁺
,
²⁷
Al
⁺
and among those
¹⁷¹
Y
⁺
has multiple ultra-narrow optical transitions suitable for serving as frequency standards [1-2].