Functionalized millimeter-scale vapor cells for alkali-metal spectroscopy and magnetometry

We describe microfabricated rubidium vapor cells with integrated temperature-control functionality and demonstrate their suitability for use in miniaturized ultrasensitive magnetometers. These functionalized vapor cells (FVCs) embody a dual-chamber design in low-conductivity silicon with antipermeation coatings and microstructured thin-film platinum surface traces as resistive heaters and temperature sensors. Thermal tests show our ability to control alkali-metal distribution within the FVCs, ensuring a clean sensing chamber for optical measurements. Optical-absorption spectroscopy is used to correlate the temperature readings with vapor density and to measure buffer-gas pressure, of interest for optimizing sensitivity. Finally, we demonstrate zero-field resonance magnetometry with 180.1em0exfT/√Hz sensitivity in the 10- to 100-Hz band, limited by laser noise and magnetic shield noise, which indicates that the functionalization does not introduce significant magnetic noise.