Wafer-scale fabrication of temperature-compensated alkali vapor cells

We demonstrate wafer-scale fabrication of temperature-compensated alkali vapor cells using a mixture of Ar and N2 buffer gases. The temperature coefficient of the fractional frequency shift of the hyperfine clock resonance is reduced from a typical value of ≈30×10−9/ K for cells containing pure N2 to below ≈3×10−9/ K for the buffer gas mixture. This result is an important step toward the mass production of temperature-compensated atomic vapor cell-based devices such as chip-scale atomic clocks.