Package design to filter GHz to THz photons for superconducting qubits

Superconducting qubits offer a promising new platform for detectors as a result of their natural sensitivity to the local environment. These devices have already demonstrated exceptional sensitivity for prototype dark matter searches due to this high sensitivity. As qubits achieve higher coherence times, the need for a low background environment becomes critical to realize their full potential as detectors. Current approaches still have significant room to optimize the local qubit environment. Through careful optimization of enclosure seams, leakage into and out of the device package can be tuned and suppressed. In this talk, an overview of flange stub filters as well as their implementation in qubit enclosures will be provided. This solution is ideal considering high thermalization, radio purity, and vacuum compatibility, which are essential for dark matter searches. The general form of these filters allows them to be well suited for a variety of quantum devices. A holistic view of how this design plays into qubit performance improvements will also be discussed.