Recent Progress on Micro-Fabricated Alkali Metal Vapor Cells

Abstract

Alkali vapor cells are the core components of atomic sensing instruments such as atomic gyroscopes, atomic magnetometers, atomic clocks, etc. Emerging integrated atomic sensing devices require high-performance miniaturized alkali vapor cells, especially micro-fabricated vapor cells. In this review, bonding methods for vapor cells of this kind are summarized in detail, including anodic bonding, sacrificial micro-channel bonding, and metal thermocompression bonding. Compared with traditional through-lighting schemes, researchers have developed novel methods for micro-fabricated vapor cells under both single- and double-beam schemes. In addition, emerging packaging methods for alkali metals in micro-fabricated vapor cells can be categorized as physical or chemical approaches. Physical methods include liquid transfer and wax pack filling. Chemical methods include the reaction of barium azide with rubidium chloride, ultraviolet light decomposition (of rubidium azide), and the high-temperature electrolysis of rubidium-rich glass. Finally, the application trend of micro-fabricated alkali vapor cells in the field of micro-scale gyroscopes, micro-scale atomic clocks, and especially micro-scale biomagnetometers is reviewed. Currently, the sensing industry has become a major driving force for the miniaturization of atomic sensing devices, and in the near future, the micro-fabricated alkali vapor cell technology of atomic sensing devices may experience extensive developments.

Quantum‐Based Magnetic Field Sensors for Biosensing

“…[13,171] For tracking of a single MNP and imaging of magnetic fields on the nanoscale, miniaturization and on-chip integration are required. Based on nanophotonic chips interfaced to microfabricated alkali vapor cells, [172][173][174] nanophotonic atomic magnetometers have the potential to provide microscale spatial resolution of magnetic field mapping.…”

A robust method for performance evaluation of the vapor cell for magnetometry

“…[1][2][3][4] A state of the art spin-exchange relaxation-free (SERF) magnetometer can achieve the best fundamental sensitivity with the advantage of a flexible configuration and low cost, making it the most promising technology in this field. [5][6][7] The core component of a SERF magnetometer is an atomic vapor cell containing an alkali metal and buffer gas; [8,9] its performance determines the sensitivity of the magnetic measurement. [10,11] Artificial operations during the fabrication process affect the components of the vapor cells, resulting in inconsistent parameters in the same batch.…”

Integrated Polarization-Splitting Grating Coupler for Chip-Scale Atomic Magnetometer

“…Motivated by urgent demand of multi-channel high-spatial resolution bio-magnetic imaging [ 9 , 10 , 11 ], micro positioning navigation-timing (MPNT) [ 12 ], ultra-low-field and zero-to-ultra low field nuclear magnetic resonance (NMR) [ 13 , 14 , 15 , 16 ], and chip integration of atomic devices has become an hot topic for researchers worldwide. While microfabricated vapor cells have attracted much attention [ 17 , 18 , 19 , 20 ], optical components manipulating the atomic state in vapor cell (optical pumping and detection) are still bulky and cumbersome (e.g., prism, polarizer, half/quarter wave plate, and polarization beam splitter). In addition, these traditional components are not compatible with nanofabrication technology, which has become major obstacle of chip integration and further miniaturization.…”