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Emerging devices such as parametric amplifiers can provide new capabilities for cryogenic sensor systems. The Quantum Sensors Group is studying a range of new devices using the powerful prototyping capability of the Boulder Microfabrication Facility.


The Novel Devices Project works at the edge of what is known and not known regarding material properties and superconducting device performance. Our recent research has focused on the development of novel devices from nitride superconductors such as TiN and NbTiN for detector and quantum information applications.


1836-MKIDs array
An 1836-MKIDs array for BLAST-TNG 250 mm band.
cryotron switch
Cryotron switch consists of AlMn signal line and Nb control line.
LED mapper
A 468-pixel cryogenic LED mapper for MKID arrays.
traveling-wave parametric amplifier
New “fishbone-style” traveling-wave parametric amplifier made from a NbTiN artificial transmission line.

Major Accomplishments

  • Development of Microwave Kinetic Inductance Detectors (MKIDs) based on Ti/TiN/Ti multilayers. This technology was developed from conception through to the fabrication of large-format sensor arrays for the BLAST-TNG balloon mission [8]. Our Ti/TiN/Ti based single photon counting detectors have also achieved the best MKID energy resolution at 1550nm near-infrared wavelength [3].
  • Novel designs for broadband quantum-limited traveling-wave parametric amplifiers based on high kinetic inductance materials reduce the physical size and pump power of these promising devices [4].
  • Novel tunable resonator [5] and tunable coupler [7] devices based on nonlinear kinetic inductance show great promise in the readout and control of quantum circuits.
  • Novel LED pixel-to-frequency mapper tool [2] and post-measurement lithographic correction technique [1] achieve perfect yield in kinetic inductance detector arrays.
  • Reinvention of superconducting cryotron circuits using modern microfabrication techniques to perform a range of switching functions at milliKelvin temperatures [6].

Recent Publications

  1. “Superconducting micro-resonator arrays with ideal frequency spacing”, X. Liu, W. Guo, Y. Wang, M. Dai, L. F. Wei, B. Dober, C. M. McKenney, G. C. Hilton, J. Hubmayr, J. E. Austermann, J. N. Ullom, J. Gao, and M. R. Vissers, Appl. Phys. Lett. 111, 252601 (2017);
  2. “Cryogenic LED pixel-to-frequency mapper for kinetic inductance detector arrays”, X. Liu, W. Guo, Y. Wang, L. F. Wei, C. M. Mckenney, B. Dober, T. Billings, J. Hubmayr, L. S. Ferreira, M. R. Vissers, and J. Gao, J. Appl., Phys. 122, 034502 2017);
  3. “Counting near infrared photons with microwave kinetic inductance detectors”, W. Guo, X. Liu, Y. Wang, Q. Wei, L. F. Wei, J. Hubmayr, J. Fowler, J. Ullom, L. Vale, M. R. Vissers, and J. Gao, Appl. Phys. Lett. 110, 212601 (2017);
  4.  “Broadband parametric amplifiers based on nonlinear kinetic inductance artificial transmission lines”, S. Chaudhuri, D. Li, K. D. Irwin, C. Bockstiegel, J. Hubmayr, J. N. Ullom, M. R. Vissers, and J. Gao, Appl. Phys. Lett. 110, 152601 (2017);
  5. “A tunable coupler for superconducting microwave resonators using a nonlinear kinetic inductance transmission line”, C. Bockstiegel, Y. Wang, M. R. Vissers, L. F. Wei, S. Chaudhuri, J. Hubmayr, and J. Gao, Appl. Phys. Lett. 108, 222604 (2016);
  6. “A thin-film cryotron suitable for use as an ultra-low-temperature switch”, P. J. Lowell, J. A. B. Mates, W. B. Doriese, G. C. Hilton, K. M. Morgan, D. S. Swetz, J. N. Ullom, and D. R. Schmidt, Appl. Phys. Lett. 109, 142601 (2016);
  7.  “Frequency-tunable superconducting resonators via nonlinear kinetic inductance”, M. R. Vissers, J. Hubmayr, M. Sandberg, S. Chaudhuri, C. Bockstiegel, and J. Gao, Appl. Phys. Lett. 107, 062601 (2015);
  8. “Photon-noise limited sensitivity in titanium nitride kinetic inductance detectors”, J Hubmayr, J Beall, D Becker, et al, Appl. Phys. Lett. 106, 073505 (2015);
Created March 7, 2018, Updated March 9, 2018