Microfabricated atomic vapor cell arrays for magnetic field measurements

Abstract

We describe a method for charging atomic vapor cells with cesium and buffer gas. By this, it is possible to adjust the buffer gas pressure in the cells with good accuracy. Furthermore, we present a new design of microfabricated vapor cell arrays, which combine silicon wafer based microfabrication and ultrasonic machining to achieve the arrays of thermally separated cells with 50 mm(3) volume. With cells fabricated in the outlined way, intrinsic magnetic field sensitivities down to 300 fT∕Hz(1∕2) are reached.

Chip-scale atomic devices

“…124 Processes have also been developed to separate and thermally isolate cells, while maintaining the rigidity of the array spacing by using a common window for all cells in the array. 139 Finally, multiple cells can be connected by channels to the same reservoir to form arrays of cells with the same buffer-gas pressure, 153 as shown in Fig. 19.…”

“…Further work 139 showed that the CsN 3 could be easily deposited inside the cells with good uniformity by first dissolving it in water and pipetting it into the cell preforms and that the UV irradiation time could be reduced to a few minutes instead of several hours by using a UV laser rather than a lamp. Finally, the alkali azide solution can be deposited on a microstructured material with large surface area to improve deposition consistency and efficiency and lower the reaction temperature.…”

Suppression of spin-exchange relaxation in tilted magnetic fields within the geophysical range

“…1. We use a microfabricated cylindrical cell (4 mm thick, 4 mm in diameter) filled with Cs-metal (I = 7/2) vapor and nitrogen as a buffer gas [33]. The density of nitrogen (0.060 amg) is chosen to be lower than the value determined to yield the lowest intrinsic magnetic linewidth [31] are unresolved.…”

Light-narrowed optically pumpedMxmagnetometer with a miniaturized Cs cell

“…Although Eq. (1) suggests large cell volume to achieve best sensitivity, we use miniaturized cavities in microfabricated cell arrays as the central sensor element [5], technologically based on recent developments of miniaturized atomic clocks and magnetometers at the National Institute of Standards and Technology (NIST) [6,7]. Several arguments like future batch production with reproducible parameters, the possibility of small spacing of (possibly connected) neighboring cells (to form well-matched gradiometers or to introduce reference cells for noise reduction [8]), or keeping external magnetic field gradients over the cell volume and between two cells as small as possible count for that strategy.…”