Chip-scale atomic platforms for sensing and timing

The separation of atomic energy levels provides a previously unobtainable accuracy and precision in metrology, with an SI traceable reference to frequency and wavelength [1]. This achievable performance is widely exploited in laboratory based atomic sensors, mainly wavelength references, clocks, interferometers, and magnetometers. As a result of the wide application range and performance gains that atomic sensors can provide, significant efforts have been made in the miniaturisation of quantum instruments to facilitate the needs of field-deployable quantum technologies.

In recent years our group has focussed on the micro-fabrication of core components that underpin the miniaturisation of atomic platforms for measurements in clocks and magnetometers [2,3]. Our research topics have included optical components to aid the miniaturisation of cold-atom sensors to the chip-scale through the development of the grating magneto-optical trap (GMOT) [4].

Beyond this, we have developed a foundation for the fabrication of micro-machined vapour cell technology, with bespoke characteristics suited to the sensor in construction.

This project will expand upon our recent research in micro-fabricated components to develop working demonstrations of a chip-scale vector magnetometer working of coherent population trapping. The system will build upon our recent work with vapour cell fabrication and environmental control of the inner vacuum pressures of these cells. Additionally, this project will utilise our expertise in micro-optics to develop novel diffractive optical elements to benefit the vector measurement while greatly reducing the package footprint for an unambiguously compact apparatus.

Finally, the core skillset learned by the student will be transferable to aiding the development of our on-chip optical clock and wavelength references, with the student being at the centre of our fabrication capabilities and project growth going forward. 1. J. Kitching, Chip-scale atomic devices, Applied Physics Reviews 5, 031302 (2018)

2. J. P. McGilligan, et. al., Laser cooling in a chip-scale platform, Applied Physics Letters 117, 054001 (2020)

3. J. A. Rushton, et. al., Contributed Review: The feasibility of a fully miniaturized magneto-optical trap for portable ultracold quantum technology, Review of Scientific Instruments 85, 121501 (2014) 4. A. Bregazzi, et al. A simple imaging solution for chip-scale laser cooling, Appl. Phys. Lett 119, 184002 (2021)

5. S. Dyer, et al. Nitrogen buffer gas pressure tuning in a micro-machined vapor cell, Appl. Phys. Lett 123, 074001 (2023)