Hoyt C W, Barber Z W, Oates C W, Fortier T M, Diddams S A, Hollberg L
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
Phys Rev Lett. 2005 Aug 19;95(8):083003. doi: 10.1103/PhysRevLett.95.083003.
We report the direct excitation of the highly forbidden (6s2) 1S0 <--> (6s6p) 3P0 optical transition in two odd isotopes of neutral ytterbium. As the excitation laser frequency is scanned, absorption is detected by monitoring the depletion from an atomic cloud at approximately 70 microK in a magneto-optical trap. The measured frequency in 171Yb (F=1/2) is 518,295,836,591.6 +/- 4.4 kHz. The measured frequency in 173Yb (F=5/2) is 518,294,576,847.6 +/- 4.4 kHz. Measurements are made with a femtosecond-laser frequency comb calibrated by the National Institute of Standards and Technology cesium fountain clock and represent nearly a 10(6)-fold reduction in uncertainty. The natural linewidth of these J=0 to J=0 transitions is calculated to be approximately 10 mHz, making them well suited to support a new generation of optical atomic clocks based on confinement in an optical lattice.
我们报告了在中性镱的两种奇数同位素中对高度禁戒的(6s2) 1S0 <--> (6s6p) 3P0光学跃迁的直接激发。当扫描激发激光频率时，通过监测磁光阱中约70微开尔文温度下原子云的损耗来检测吸收。在171Yb（F = 1/2）中测得的频率为518,295,836,591.6 +/- 4.4千赫兹。在173Yb（F = 5/2）中测得的频率为518,294,576,847.6 +/- 4.4千赫兹。测量是使用由美国国家标准与技术研究院铯喷泉钟校准的飞秒激光频率梳进行的，不确定性降低了近10^6倍。这些J = 0到J = 0跃迁的自然线宽经计算约为10毫赫兹，这使其非常适合用于支持基于光学晶格囚禁的新一代光学原子钟。
