Frequency stabilization of 423 nm laser for calcium-beam optical frequency standard

The Ca beam optical frequency standard has the potential to be small optical clock like small Cs beam clock in microwave regime. For improving the signal-to-noise ratio of the clock transition spectroscopy, the electron shelving detection, which uses the fast
¹
S
₀
-
¹
P
₁
423nm transition to detect the narrow
¹
S
₀
-
³
P
₁
657nm clock transition, was applied for Ca beam optical frequency standard. Therefore the frequency stability of 423 nm laser to some extent determines the performance of the optical frequency standard. In this paper, we stabilize the 423 nm laser frequency to Ca beam signal with side-band locking technique and estimate the preliminary stability of 423 nm laser which is 1.4×10
^-11
at 1 s and 2×10
^-12
at 100 s.