A comparison of two 40Ca+ single ion optical clocks at 5×10-17

8^th International Conference and Exhibition on Lasers, Optics & Photonics

November 15-17, 2017 | Las Vegas, USA

Hua Guan, Yao Huang and Kelin Gao

Chinese Academy of Sciences, China

Scientific Tracks Abstracts: J Laser Opt Photonics

Abstract :

A comparison of two optical clocks and a detailed study of the systematic frequency shifts of each 40Ca+ single-ion optical clock were carried out in WIPM. A Ti:sapphire laser at 729 nm is frequency stabilized to an ultra-stable ultra-low thermal expansion coefcient (ULE) cavity by means of Pound-Drever-Hall method. 1 Hz linewidth and 2��10�15 frequency stability at 1-100 s is realized. Which is used for the probe of 40Ca+ optical transition. After compensating for the micromotion, the two optical clocks both reach an uncertainty level of a few parts in 10�17. The dominant source of uncertainty is the blackbody radiation (BBR) shift after minimizing the micromotion-induced shifts. The BBR shift is evaluated by controlling and measuring the temperature at the trap center. With a measurement over one month, the frequency difference between the two clocks is measured to be 3.2 (5.5)��10�17. Due to improvement of the clock laser and better control of the optical and electromagnetic feld geometry and the laboratory conditions, a fractional stability of 7��10�17 in 20,000 s of averaging time is achieved. The absolute frequency of the 40Ca+ 4s 2S1/2- 3d 2D5/2 clock transition is measured to be 411 042 129 776 401.7 (1.1) Hz, with a fractional uncertainty of 2.7 �� 10�15 using the GPS satellites as a link to the SI second.

Biography :

Hua Guan has completed his PhD from Wuhan Institute of Physics and Mathematics (WIPM), The Chinese Academy of Sciences (CAS) and he visited NIST Boulder twice between 2008-2010. He is a Professor of WIPM. His major is Precision Measurement Physics. And his research interests are single-ion optical clocks and trapped ion precise spectroscopy. He has published more than 20 papers, including Phys. Rev. Lett., Phys. Rev. A, Appl. Phys. B, Rev. Sci. Instum. etc