Compact, low-power chip-scale atomic clock

We have successfully demonstrated a compact atomic frequency standard, the Chip-Scale Atomic Clock (CSAC), which achieves aggressive reductions in size and power while preserving good short-term stability. The device, based on Coherent Population Trapping (CPT), achieved volume less than 1 cm³, power consumption below 30 mW, and an Allan Deviation less than 1 times 10^-11 (1 hour). This device incorporated a novel dual-pass reflective optical configuration based on a microstructured dual focus optic. Compact, low-power control electronics were developed based on an injection-locked voltage controlled oscillator (VCO) circuit. This approach enabled the combined power consumption of the VCO and microcontroller-based control electronics to be kept below 15 mW.