Accessing Nonlinearity in Superconducting Millimeter Wave Coplanar Resonators

Current superconducting quantum systems rely on ultra-cold temperatures to reduce sources of noise and quantum decoherence. While many advances have been made in the purification and refinement of quantum devices in the low microwave frequency range, millimeter frequencies have been far less explored. Using higher energy photons as a building block could potentially allow quantum experiments to be run faster, at higher temperatures, and easily access other high frequency quantum systems, such as Rydberg atoms. We use superconducting thin film materials to fabricate resonators with planar geometries to ensure scalability and direct compatibility with other elements in the superconducting quantum toolbox, while gaining a natural increase of kinetic inductance based nonlinear effects with frequency. Here, we present and characterize low-loss millimeter wave resonators with planar geometries exhibiting nonlinear behavior, demonstrating a scalable core component for a new generation of high frequency quantum devices.