Precision frequency measurement of visible intercombination lines of strontium.
We report the direct frequency measurement of the visible 5s(2) 1S0-5s5p 3P1 intercombination line of strontium that is considered a possible candidate for a future optical-frequency standard. The frequency of a cavity-stabilized laser is locked to the saturated fluorescence in a thermal Sr atomic beam and is measured with an optical-frequency comb generator referenced to the SI second through a global positioning system signal. The 88Sr transition is measured to be at 434 829 121 311 (10) kHz. We measure also the 88Sr-86Sr isotope shift to be 163 817.4 (0.2) kHz.
Ferrari
G
G
Dipartimento di Fisica and LENS, Università di Firenze, INFM-UdR Firenze, Polo Scientifico, 50019 Sesto Fiorentino, Italy.
Cancio
P
P
Drullinger
R
R
Giusfredi
G
G
Poli
N
N
Prevedelli
M
M
Toninelli
C
C
Tino
G M
GM