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arXiv 1702.02813physics.ins-detcond-mat.mes-hall
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超导纳米线单光子探测器中的Fano涨落

Fano fluctuations in superconducting nanowire single-photon detectors

A. G. Kozorezov, C. Lambert, F. Marsili, M. J. Stevens, V. B. Verma, J. P. Allmaras, M. D. Shaw, R. P. Mirin, Sae Woo Nam

摘要:

由于Fano涨落的普适性,它将影响超导纳米线单光子探测器(SNSPD)的响应。我们预测,光子计数率($PCR$)作为偏置电流($I_B$)的函数在SNSPD描述的横向坐标相关的互补误差函数的积分。后者描述了由于沉积到电子系统中的能量的量的Fano波动引起的局部响应的拖尾。$PCR$与$I_B$的有限宽度$σ$源自能量下转换级联期间准粒子与声子之间的能量分配中的波动。在窄纳米线SNSPD中,局部响应是均匀的,并且Fano涨落对$σ$的影响占主导地位。在宽纳米线SNSPD中,由于涡旋-反涡旋解束缚和涡旋从边缘进入,局部响应具有较强的坐标依赖性,Fano波动涂抹了$PCR$曲线过渡部分上的涡旋印记奇点。我们表现出良好的理论和实验之间的一系列浴温度和光子能量在窄线WSi SNSPD。由Fano波动预测的时间分辨热点弛豫曲线与实验中观察到的洛伦兹形状在整个偏置电流范围内相匹配,除了它们的尾部。

英文摘要:

Because of their universal nature, Fano fluctuations are expected to influence the response of superconducting nanowire single-photon detectors (SNSPDs). We predict that photon counting rate ($PCR$) as a function of bias current ($I_B$) in SNSPDs is described by an integral over a transverse coordinate-dependent complementary error function. The latter describes smearing of local responses due to Fano fluctuations of the amount of energy deposited into electronic system. The finite width, $σ$, of the $PCR$ vs $I_B$ arises from fluctuations in the energy partition between quasiparticles and phonons during the energy down-conversion cascade. In narrow-nanowire SNSPDs the local responses are uniform, and the effect of Fano-fluctuations on $σ$ is dominant. In wide-nanowire SNSPDs with strong coordinate dependence of local responses due to vortex-antivortex unbinding and vortex entry from edges, Fano-fluctuations smear singularities imprinted by vorticity on the transition part of $PCR$ curve. We demonstrate good agreement between theory and experiments for a series of bath temperatures and photon energies in narrow-wire WSi SNSPDs. The time-resolved hotspot relaxation curves predicted by Fano fluctuations match the Lorentzian shapes observed in experiments over the whole range of bias currents investigated except for their tails.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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