Towards single-photon optomechanical coupling using superconducting quantum interference

Cavity optomechanics explores the interaction between mechanical oscillators and electromagnetic modes via radiation-pressure. Various milestone experiments have been conducted using different optomechanical platforms, such as ground-state cooling and the generation of non-classical states. These experiments employed a first-order linearized dispersive interaction due to the small single-photon coupling rate between the two modes. Enhancing this coupling is crucial for unlocking higher-order and nonlinear interaction terms and for enabling sophisticated experiments like the generation of mechanical cat states. Flux-mediated optomechanics (FMOM) is a strong candidate for unlocking the single-photon regime. In FMOM, a microbeam is integrated into a SQUID, and the coupling is achieved by transducing the beam displacement into a flux change in the SQUID via a large external in-plane field. The usually small single-photon coupling rate will be proportional to the strength of the magnetic field, and therefore it is crucial to implement FMOM with field-resilient superconductors. Our poster presents the progress and discusses the challenges in developing niobium-based FMOM devices, a promising material candidate for Tesla-field compatibility.