Magnetic field resilient superconducting coplanar waveguide resonators for hybrid circuit QED experiments

Superconducting co-planar waveguide (CPW) resonators have proven to be powerful tools in astronomy, microwave microscopy and quantum information processing. They are crucial components in superconducting circuits, and numerous proposals aim to utilise them in scalable solid-state quantum computers, topological computing schemes and hybrid qubit candidates. Many of these proposals require application of magnetic fields strong enough to introduce Abrikosov vortices or destroy the superconductivity entirely, significantly reducing the internal quality factors (Q_i) and causing frequency fluctuations that would render the resonator useless. Here we report the design and fabrication of NbTiN superconducting CPW resonators that retain stable resonance frequencies and single photon Q_is ∼ 100,000 in parallel fields up to B_|| = 5.5 T and perpendicular fields of B_⊥ = 20 mT. We demonstrate this field resilience results from two factors: expulsion of vortices by careful reduction of the superconducting film thickness and control of vortex dynamics via patterning with etched vortex pinning sites. Finally, we apply these techniques to perform fast charge readout of a hybrid InSb nanowire double quantum dot device at 1 T.