Absolute Frequency Measurement of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Li</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>6</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>D</mml:mi></mml:math>Lines with khz-Level Uncertainty
Rui Li, Yuelong Wu, Yang Rui, Li Bo, Yan‐Yi Jiang, Long-Sheng Ma, Haibin Wu
Abstract
We report the precision measurement of the absolute frequencies, hyperfine splitting, and 2P fine structure splitting in cold atoms of ^{6}Li. Using the stabilized optical frequency comb and developed heterodyne detection technique, the photon shot-noise limited optical spectroscopy is achieved. The measurement of absolute frequencies of D_{1} lines is reached with an uncertainty of about 1 kHz, which is 1 order of magnitude more accurate than previous measurements. The hyperfine splitting of the D_{1} line and 2P fine structure splitting of ^{6}Li are 26.103 1 (14) and 10 052.780 4 (18) MHz, respectively, in agreement with recent theoretical calculations. Our results could provide a benchmark to test the theory at the higher precision and help to resolve large discrepancies among previous experiments.