Wafer-Scale Diamond Grinding Of 3D Optical Accessible Vacuum Cells for Quantum Technologies

Micro-scale vacuum cells with 3D optical access are of increasing interest for the miniaturisation and, ultimately, the commercialisation of atom traps for use in quantum sensing. Cleanroom-based plasma or chemical etching is not a viable fabrication route for ≥mm scale wells and vias due to poor vertical side-wall optical quality and throughput. The community has looked towards alternative approaches, such as reflow moulding [1] and additive manufacturing [2], although these approaches are potentially labour-intensive or yield poor surface quality. Physical machining using diamond tooling has successfully produced silicon frames for vapour cells [3]. However, to produce a fully precision machined 3D optical accessible cell, the internal sidewalls must be of optical quality without requiring subsequent polishing and in a suitable optically transparent material.