Millimeter-wave superconducting devices offer a platform for quantum experiments at temperatures above 1 K, and new avenues for studying light-matter interactions in the strong coupling regime. Using the intrinsic nonlinearity associated with kinetic inductance of thin-film materials, we realize four-wave mixing at millimeter-wave frequencies, demonstrating a key component for superconducting quantum systems. We report on the performance of niobium nitride resonators around 100 GHz, patterned on thin (20–50-nm) films grown by atomic layer deposition, with sheet inductances up to $212\mathrm{pH}/◻$ and critical temperatures up to 13.9 K. For films thicker than 20 nm, we measure quality factors from $1\times {10}^4$ to $6\times {10}^4$, and explore potential loss mechanisms. Finally, we measure degenerate parametric conversion for a 95-GHz device with a forward efficiency up to $+16\mathrm{dB}$, paving the way for the development of nonlinear quantum devices at millimeter-wave frequencies.

• Received 6 September 2019
• Revised 11 December 2019
• Accepted 9 January 2020

DOI:https://doi.org/10.1103/PhysRevApplied.13.024056