Finite element analysis (FEA) based design optimization of ultrastable, high finesse optical cavities for portable optical atomic clock applications

Optical atomic clocks, with their exceptional frequency stability and accuracy, have transformed timekeeping, enabling applications in fields like geodesy, fundamental physics, and global navigation. The development of transportable optical clocks has expanded their use to field environments, but challenges like robustness and environmental sensitivity remain. A critical component for clock precision is ultra-stable laser systems, stabilized using high-finesse optical cavities. In this study, we perform Finite Element Analysis (FEA) on cubic spacer ultra-stable cavities to assess their mechanical stability and sensitivity to external forces. By analyzing various parameters, including truncation cutout depth, support length, bore diameter, and cubic spacer size, we identify the optimal cavity design to minimize fractional length instability. Simulations are performed under idealized conditions, excluding gravitational effects, to isolate the influence of compressive holding forces on cavity deformation. Our results, benchmarked against published data, show close agreement, with minor discrepancies likely due to differences in boundary conditions or mesh convergence. This validation provides confidence in our approach and sets the stage for future studies on larger cubic spacer cavities. This research offers critical insights for optimizing cavity design, ultimately enhancing the robustness and performance of optical atomic clocks in both laboratory and field settings.