Progress of Active Optical Frequency Standard based on thermal Ca atomic beam

The experiment system for Active Optical Frequency Standard(AOFS) based on thermal Ca atomic beam has been set up. Making use of magnetic field for the atomic beam, we have realized population inversion between ground state
¹
S
₀
and metastable state
³
P
₁
(m=0) which is primary for AOFS. Detection results are presented by applying electron-shelving technique on thermal Ca atomic beam.