Broadband Sample Holder for Microwave Spectroscopy of Superconducting Qubits

TL;DR

This paper introduces a practical broadband sample holder for microwave spectroscopy of superconducting qubits, compatible with dilution cryostats, covering 0-32 GHz, and tested successfully with a flux qubit at millikelvin temperatures.

Contribution

A novel, easy-to-integrate broadband sample holder design for microwave experiments with superconducting circuits at millikelvin temperatures.

Findings

Flat pass band response from 0 to 32 GHz.

Effective suppression of parasitic higher modes.

Successful characterization of a superconducting flux qubit.

Abstract

We present a practical design and implementation of a broadband sample holder suitable for microwave experiments with superconducting integrated circuits at millikelvin temperatures. Proposed design can be easily integrated in standard dilution cryostats, has flat pass band response in a frequency range from 0 to 32 GHz, allowing the RF testing of the samples with substrate size up to 4x4 mm. The parasitic higher modes interference in the holder structure is analyzed and prevented via design considerations. The developed setup can be used for characterization of superconducting parametric amplifiers, bolometers and qubits. We tested the designed sample holder by characterizing of a superconducting flux qubit at 20 mK temperature.