2013/03/08 by L. J. Swenson, Peter K. Day, P. K. Day +12 · 1 citation
Engineering · Physics and Astronomy · #Photonic and Optical Devices #Physics of Superconductivity and Magnetism #Superconducting and THz Device Technology #astro-ph.IM #cond-mat.supr-con
paper · pdf · doi:10.1063/1.4794808
published as J. Appl. Phys. 113, 104501 (2013)
openalex publication_date 2013/03/08 · arxiv created 2013/05/18 · arxiv updated 2013/05/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
If driven sufficiently strongly, superconducting microresonators exhibit nonlinear behavior including response bifurcation. This behavior can arise from a variety of physical mechanisms including heating effects, grain boundaries or weak links, vortex penetration, or through the intrinsic nonlinearity of the kinetic inductance. Although microresonators used for photon detection are usually driven fairly hard in order to optimize their sensitivity, most experiments to date have not explored detector performance beyond the onset of bifurcation. Here, we present measurements of a lumped-element superconducting microresonator designed for use as a far-infrared detector and operated deep into the nonlinear regime. The 1 GHz resonator was fabricated from a 22 nm thick titanium nitride film with a critical temperature of 2 K and a normal-state resistivity of 100 μΩ cm. We measured the response of the device when illuminated with 6.4 pW optical loading using microwave readout powers that ranged from the low-power, linear regime to 18 dB beyond the onset of bifurcation. Over this entire range, the nonlinear behavior is well described by a nonlinear kinetic inductance. The best noise-equivalent power of 2×10−16 W/Hz1/2 at 10 Hz was measured at the highest readout power, and represents a ∼10 fold improvement compared with operating below the onset of bifurcation.