Lifetime assessment of RbN_3-filled MEMS atomic vapor cells with Al_2O_3 coating

Abstract

Micro-fabricated (MEMS) alkali vapor cells are at the heart of the miniaturization of atomic devices such as atomic magnetometers, atomic gyroscopes and atomic clocks. Among the different techniques used to fill microfabricated alkali vapor cell, UV decomposition of rubidium azide (RbN₃) into metallic Rb and nitrogen in Al₂O₃ coated cells is a very promising approach for low-cost wafer-level fabrication. Here we present a detailed lifetime study of such cells. The rubidium consumption being the main identified cell failure mode, it is monitored with an novel image analysis technique and with high temperature long term aging tests.

Chip-scale atomic devices

“…A more detailed assessment of the long-term physical stability of cells with Al 2 O 3 coatings filled using the CsN 3 method was carried out. 143 By measuring the size of the alkali metal droplets observed on the inside glass surface of a microfabricated vapor cell as a function of time, it was determined that roughly 1 lg of alkali metal would suffice for a cell operated at 95 C for 10 yr. An important aspect of vapor cells used in atomic clocks is the stability of the buffer gas pressure over long periods. As described above, small changes in the pressure can lead to drifts of the clock output frequency through the pressure shift.…”

Microfabricated Vapor Cells with Reflective Sidewalls for Chip Scale Atomic Sensors

“…In order to avoid the reverse reaction of conventional rubidium compounds, the approach of dispenser pills is applied. There are several hermeticity measurement approaches [ 50 , 51 ], and in our work aging tests were implemented, being mainly based on the leak rate measurement.…”

Laser-written vapor cells for chip-scale atomic sensing and spectroscopy

“…The introduced laser-writing technique provides a suitable interaction volume for precision atomic spectroscopy and atomic quantum sensing with 3D structuring versatility and it has high potential for integration with waveguide-based photonic structures [62,67,68] and optical components [9,10] as well as with optical fibers for chipscale [29] and fiber-coupled [79] atomic sensors. As further development, different geometries and filling techniques based on alkali metal azide [80], mixture of argon and nitrogen [70] as well as other noble gas species like 3 He and 129 Xe [81], will be implemented to optimize specific applications as atomic references, atomic clocks, optical magnetometers and atomic gyroscopes. Finally, the use of NEG dispensers is an attractive feature for miniaturized cold-atoms sensors and compact ultracold quantum technologies [39,69,82].…”