CPT atomic clock with cold-technology-based vapour cell

•All-direct-bonded Rb cells for highly stable mini atomic clocks is firstly reported.•Applied fabrication technology is low-temperature in contrast to alternative ones.•Proposed fabrication method provides perfect repeatability of cell parameters.•Tests demonstrate competitive atomic clock stability at the 5 × 10–12 level over 1000 s.•New vapour cell technology is compatible with a wide range of optical materials. Alkali-metal vapour cells are the core of coherent population trapping (CPT) atomic clocks, devices with a multitude of applications. These cells ensure high clock stability due to an atomic reference resonance. The contemporary technologies of alkali-metal vapour cells for atomic clocks compatible with mass production are relatively complicated and require special materials, as well as sub-technologies. The present work for the first time studies atomic CPT cocks with rubidium miniature cells fabricated with a simpler direct optical bonding technology, which has never hitherto been used for this purpose. The proposed technology can be implemented both in industrial and in laboratory setting. The measured stability of CPT atomic clock with rubidium cells fabricated with this technology amounted to 4 × 10–11 over 1 s and 1.3 × 10–12 over 103 s. The generated results indicate that the direct optical bonding technology can be successfully utilised for fabrication of compact cells with alkali-metal vapours for metrological and sensor applications.