Dynamics of Hotspot Formation, in Nanostructured Superconducting Stripes Excited with Single Photons
A. Jukna a, b, J. Kitaygorsky a, D. Pan a, A. Cross a, A. Perlman a, I. Komissarov a, R. Sobolewski a, O. Okunev c, K. Smirnov c, A. Korneev c, G. Chulkova c, I. Milostnaya c, B. Voronov c and G.N. Gol'tsman c
a Department of Electrical and Computer Engineering and Laboratory for Laser Energetics, University of Rochester, Rochester NY 14627-0231, USA
b High-Tc-Superconductivity Laboratory, Semiconductor Physics Institute, A. Goštauto 11, LT-01108 Vilnius, Lithuania
c Department of Physics, Moscow State Pedagogical University, 119992 Moscow, Russia
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Received: 26 08 2007;
Dynamics of a resistive hotspot formation by near-infrared-wavelength single photons in nanowire-type superconducting NbN stripes was investigated. Numerical simulations of ultrafast thermalization of photon-excited nonequilibrium quasiparticles, their multiplication and out-diffusion from a site of the photon absorption demonstrate that 1.55 μm wavelength photons create in an ultrathin, two-dimensional superconducting film a resistive hotspot with the diameter which depends on the photon energy, and the nanowire temperature and biasing conditions. Our hotspot model indicates that under the subcritical current bias of the 2D stripe, the electric field penetrates the superconductor at the hotspot boundary, leading to suppression of the stripe superconducting properties and accelerated development of a voltage transient across the stripe.
DOI: 10.12693/APhysPolA.113.955
PACS numbers: 74.25.Fy, 74.25.Sv, 74.45.+c