Cs microcell optical reference with frequency stability in the low 10^-13 range at 1 s

We describe a high-performance optical frequency reference based on dual-frequency sub-Doppler spectroscopy (DFSDS) using a Cs vapor microfabricated cell and an external-cavity diode laser at 895 nm. Measured against a reference optical signal extracted from a cavity-stabilized laser, the microcell-stabilized laser demonstrates an instability of 3 × 10^-13 at 1 s, in agreement with a phase noise of +40 dBrad²/Hz at 1-Hz offset frequency, and below 5 × 10^-14 at 10² s. The laser short-term stability limit is in good agreement with the intermodulation effect from the laser frequency noise. These results suggest that DFSDS is a valuable approach for the development of ultra-stable microcell-based optical standards.