Evaluation of systematic shifts for the 88Sr+ 445-THz Reference transition at the 10−17 level using the NRC next generation ion trap system

We describe recent progress in the establishment of a versatile and reliable optical frequency standard whose performance in evaluated accuracy and stability exceeds that of the current realization of the SI second. The 445-THz reference transition in a single, trapped, and laser cooled ion of ⁸⁸Sr⁺ suspended using a miniature RF endcap trap system has been observed to obtain transform limited linewidths below 5 Hz. The micromotion induced shifts of the ion system in the new trap have been reduced to the 2 × 10^-17 level for each of the scalar Stark shifts and the time dilation shifts. Studies indicate that such shifts remain stable over several hours. An identical trap system was constructed to evaluate the electrode heating effects of the ion trap during operation and the resulting Blackbody radiation shifts. Evaluation of these effects indicate that the uncertainty of shift will be limited by the current knowledge of the scalar polarizabilities of the upper and lower states of the reference transition, currently at the 2 × 10^-17 level.