Yang Xiaoyan, Li Hao, Zhang Weijun, You Lixing, Zhang Lu, Liu Xiaoyu, Wang Zhen, Peng Wei, Xie Xiaoming, Jiang Mianheng
Opt Express. 2014 Jun 30;22(13):16267-72. doi: 10.1364/OE.22.016267.
Dark count rate is one of the key parameters limiting the performance of the superconducting nanowire single photon detector (SNSPD). We have designed a multi-layer film bandpass filter that can be integrated onto the SNSPD to suppress the dark counts contributed by the stray light and blackbody radiation of the fiber. The bandpass filter is composed of 16 SiO(2)/Si bilayers deposited onto the backside of a thermally oxidized Si substrate. The substrate shows an excellent bandpass filter effect and provides a high transmittance of 88% at the central wavelength of the pass band, which is the same as that of the bare substrate. The SNSPDs fabricated on the substrate integrated with the bandpass filter show conspicuous wavelength-sensitive detection efficiency. The background dark count rate is reduced by two orders of magnitude to sub-Hz compared with the conventional SNSPD (a few tens of Hz). The detector exhibits a system detection efficiency of 56% at DCR of 1 Hz, with the measured minimal noise equivalent power reaching 2.0 × 10(-19) W/Hz(1/2).
暗计数率是限制超导纳米线单光子探测器（SNSPD）性能的关键参数之一。我们设计了一种多层薄膜带通滤波器，可集成到SNSPD上，以抑制由光纤的杂散光和黑体辐射产生的暗计数。该带通滤波器由沉积在热氧化硅衬底背面的16个SiO(2)/Si双层组成。该衬底显示出优异的带通滤波效果，在通带中心波长处提供88%的高透过率，与裸衬底相同。在集成了带通滤波器的衬底上制造的SNSPD表现出明显的波长敏感探测效率。与传统的SNSPD（几十Hz）相比，背景暗计数率降低了两个数量级，降至亚Hz。该探测器在1 Hz的暗计数率下系统探测效率为56%，测量的最小噪声等效功率达到2.0×10(-19) W/Hz(1/2)。
