Prof. Karl K. Berggren
Research Laboratory of Electronics
Massachusetts Institute of Technology (MIT)
Superconducting nanowires have long been of use in single-photon detection for applications in quantum information science. However, only recently have we begun to study them as a unique platform for examining how systems with low electronic carrier densities behave. These thin film materials are characterized by relatively high critical temperatures, i.e. as being “good” superconductors, but also high resistivities, i.e. as being “bad” metals. In this regime, kinetic inductance (the inductance associated with inertial motion of charge carriers) dominates over conventional magnetic inductance. As a result, devices can exhibit ultralow phase velocities in the microwave spectral region. These characteristics result in opportunities for new applications. Superconducting-nanowire-based single-photon detectors have already been applied to problems ranging from LIDAR to integrated-circuit evaluation. With our newfound understanding of the microwave plasmonic properties of these materials, applications may be envisaged that take advantage of the slow electromagnetic propagation speeds in the materials, the tunability of kinetic inductance, and the ability to integrate these materials with interesting technologies, e.g. with photonic and superconducting quantum systems.