Direct Laser Cooling Al+ Ion Optical Clocks

• 来源期刊: 中国物理快报（英文版）
• 关键词: @@
• 年，卷（期）: 2017,（5）
• 页码范围: 31-35
• 页数: 5页
• 语种: 英文
• DOI: 10.1088/0256-307X/34/5/050601

摘要

The Al+ ion optical clock is a very promising optical frequency standard candidate due to its extremely small black-body radiation shift.It has been successfully demonstrated with the indirect cooled,quantum-logic-based spectroscopy technique.Its accuracy is limited by second-order Doppler shift,and its stability is limited by the number of ions that can be probed in quantum logic processing.We propose a direct laser cooling scheme of Al+ ion optical clocks where both the stability and accuracy of the clocks are greatly improved.In the proposed scheme,two Al+ traps are utilized.The first trap is used to trap a large number of Al+ ions to improve the stability of the clock laser,while the second trap is used to trap a single Al+ ion to provide the ultimate accuracy.Both traps are cooled with a continuous wave 167nm laser.The expected clock laser stability can reach 9.0 × 10-17/√τ.For the second trap,in addition to 167nm laser Doppler cooling,a second stage pulsed 234nm two-photon cooling laser is utilized to further improve the accuracy of the clock laser.The total systematic uncertainty can be reduced to about 1 × 10-18.The proposed Al+ ion optical clock has the potential to become the most accurate and stable optical clock.