Polymer-loaded three dimensional microwave cavities for hybrid quantum systems

TL;DR

This paper investigates how polymer materials affect the resonance and energy dissipation in 3D microwave cavities, providing parameters for improved cavity design in hybrid quantum systems.

Contribution

It introduces a method to characterize polymer dielectric properties and demonstrates cavity tuning for quantum applications with polymer-filled resonators.

Findings

Polymer dielectric properties were measured and characterized.

Cavity resonance can be tuned using polymer-filled structures.

Successful matching of a polymer-filled cavity to rubidium hyperfine transition.

Abstract

Microwave cavity resonators are crucial components of many quantum technologies and are a promising platform for hybrid quantum systems, as their open architecture enables the integration of multiple subsystems inside the cavity volume. To support these subsystems within the cavity, auxiliary structures are often required, but the effects of these structures on the microwave cavity mode are difficult to predict due to a lack of a priori knowledge of the materials' response in the microwave regime. Understanding these effects becomes even more important when frequency matching is critical and tuning is limited, for example, when matching microwave modes to atomic resonances. Here, we study the microwave cavity mode in the presence of three commonly-used machinable polymers, paying particular attention to the change in resonance and the dissipation of energy. We demonstrate how to use the derived dielectric coefficient and loss tangent parameters for cavity design in a test case, wherein we match a polymer-filled 3D microwave cavity to a hyperfine transition in rubidium.