Characterization of 894.6 nm VCSELs and application to a microcell-based atomic clock

International audienceWe report the characterization of 894.6 nm verticalcavity surface-emitting lasers (VCSELs). The laser RIN is -105 dB/Hz at 1 Hz offset frequency for a laser power of 50 μW. The laser spectral linewidth is measured to be about 31.8 MHz. Such a VCSEL is used in a Cs-Ne microcell-based atomic clock prototype based on coherent population trapping (CPT). A preliminary fractional frequency stability of 3.8 10-11 τ-1/2 up to 1000 s and lower than 3 10-11 at 60 000 s averaging time is reported. Further tests are in progress to improve the clock mid-term and long-term frequency stability