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1.
本文主要研究了作为可见光和近红外光波段Nb基单光子探测器.在本文中概述了Nb+Al结构的超导纳米线单光子探测器(SNSPD)的制备,并对制备出的SNSPD器件进行了直流表征,测试了其超导转变温度,并从中选取了直流特性良好的样品进行了光学表征.当单光子探测器被一个直流偏置在其临界电流以下并接近临界电流值时,激光器发出的1550nm波段的光子脉冲到达单光子探测器,使其产生电学信号.20nm厚的SNSPD不能对单光子产生反应;5nm厚的SNSPD可以探测单个光子,并且计算了其系统探测效率.  相似文献   

2.
对铌/铝超导纳米线单光子探测器(SNSPD)的光耦合结构和性能表征进行了研究。通过溅射与剥离的方法制作了超薄铌/铝SNSPD,设计了带有激光准直器的光耦合结构和封装方法,并搭建了可靠的低温测试系统。在700m K下表征了SNSPD的直流特性,得到了单光子响应脉冲和1550nm波长下的探测效率,并研究了探测效率和暗计数率与偏置电流的关系。  相似文献   

3.
超导纳米线单光子探测器件(SNSPD)是超导单光子探测系统的核心器件。文中介绍了成功制备的基于5nm厚的NbN超导超薄薄膜的SNSPD器件。器件核心结构为150nm宽的纳米曲折线结构,纳米线条占空比为75%,面积为20μm×20μm。超导纳米线是利用电子束曝光(EBL)技术和反应离子刻蚀(RIE)等工艺技术制备的。所制备的SNSPD样品,在温度3.5K下的临界电流约12.9μA;在1310nm波长光波辐照,12.5μA的偏置电流下,探测效率约0.016%。  相似文献   

4.
超导纳米线单光子探测器(SNSPD)因其优异的综合性能被广泛应用于量子通信等众多领域,然而其独特的线性结构会导致SNSPD的探测效率对入射光的偏振态具有依赖性,从而限制了SNSPD在非常规光纤链路或其他非相干光探测环境中的应用.本文基于传统的回形纳米线结构设计制备了一种新型偏振不敏感SNSPD,在纳米线周围引入一层高折射率Si薄膜作为介质补偿层来提高纳米线对垂直偏振态入射光的吸收效率,并将补偿层的上表面设计为光栅结构以减小不同波长下纳米线对不同偏振态入射光的吸收差异从而实现在特定波长范围内的偏振不敏感.除此之外,还采用介质镜和双层纳米线结构来提高器件的光吸收效率,测试结果表明该器件在1605 nm波长处最大探测效率为87%,对应的偏振消光比为1.06.该工作为未来实现高探测效率的偏振不敏感SNSPD提供了参考依据.  相似文献   

5.
超导纳米线单光子探测器(SNSPD)的系统探测效率由纳米线与光子的耦合效率、纳米线的吸收效率以及纳米线吸收光子后能产生电压脉冲的本征量子效率决定。设计了一种带有防反射层、谐振腔、布拉格反射镜等结构的SNSPD。利用COMSOL软件的射频模块对这种新型结构的SNSPD进行了仿真,结果表明具有光学结构的SNSPD将有助于提高系统探测效率。  相似文献   

6.
超导纳米线单光子探测器(SNSPD)具有探测效率高、暗计数低等优点,但通常工作在非线性模式,不具备光子数分辨的能力.在线性光学、量子计算等许多领域,通常还要求探测器能够对入射的光子数进行分辨.目前基于超导纳米线单光子探测器实现光子数分辨主要有三种途径:阵列结构的读出电路非常复杂,并联纳米线探测器(PND)的漏电流限制了最多可分辨的光子数目和系统效率,串联纳米线探测器(SND)的读出电路简单,而且没有漏电流,理论上可以分辨大量的光子数目,同时获得较高的系统效率.本文基于串联纳米线探测器结构,设计了一种6像元串联纳米线探测器,即6个纳米线单元串联,每个纳米线单元两端并联一个电阻RP.实验结果表明,在不同光功率下,该结构可以实现6个光子的分辨,而且可以工作在0.97IC,没有漏电流影响.  相似文献   

7.
超导纳米线单光子探测器是新型超导电子器件,因其具有高探测效率、低暗计数及低时间抖动等优势,在量子信息、激光雷达等方面已得到广泛的应用.目前主流超导纳米线单光子探测器主要工作在1.5_m 以下的可见光和近红外波段.中红外波长的红外探测技术在基础科学、医学、日常生活以及军事等广泛领域发挥着重要作用,中红外单光子探测器可以使得中红外波段探测技术进入量子极限灵敏度.根据超导纳米线单光子探测器探测机理,超窄线宽的纳米线条可以提升超导纳米线单光子探测器在中红外波长的灵敏度.电子束曝光技术是目前实现超导纳米线单光子探测器纳米线线条加工的主流技术,电子束抗蚀剂种类繁多,面向超窄线宽超导纳米线单光子探测器器件的制备需求,对两款抗蚀剂进行性能测试表征,和窄纳米线制备尝试.根据负性电子束抗蚀剂MaN-2401在制备窄线宽时的显著优点,优化工艺,利用其成功制备出50nm 线宽超导纳米线单光子探测器并成功实现了2000nm 的单光子响应.  相似文献   

8.
本文研究具有强吸收结构的高速超导纳米线单光子探测器(SNSPD)的设计与仿真.该SNSPD基于高折射率入射介质和空气腔结构,可以提高超导纳米线的光子吸收率.与现有超导单光子探测器结构相比,在相同材料和厚度的超导超薄膜制成纳米线的条件下,用更低的占空比就可以实现接近于100%的吸收率,这使得电子束曝光步骤的难度大大降低.而SOI衬底的采用则可以同时保证超导薄膜的高质量生长,不影响探测器的本征量子效率.另外,在保证同样大的有效探测面积的条件下,由于需要的纳米线的总长度显著减小,制备过程中发生缺陷的概率显著降低,探测器的最高计数率可以得到提升.  相似文献   

9.
超导纳米线单光子探测器(SNSPD)因其优异的综合性能,在量子信息、激光雷达等方面有广泛的应用.通常, SNSPD工作在直流偏置下,在时域上具有自由运行探测的优点.而在卫星激光测距、单光子激光雷达等光信号到达时间有规律的应用场景中,使用交流偏置有望提升器件运行速率、有效抑制背景暗计数,却存在信号读出困难的棘手问题.本文报道了自差分读出的交流偏置SNSPD系统,该系统包含两根并行排布纳米线构成的2-pixel SNSPD器件.给两根纳米线加载相同的100 MHz交流偏置信号,并对两路输出信号差分使噪声信号相抵消,实现光子响应信号的读出.基于该方法测得,响应信号的信噪比相比差分之前提升10倍,在交流偏置下器件的暗计数降低至直流偏置下的约1/4,计数率达到直流偏置下的约1.5倍.本文为交流偏置SNSPD测试提供了一种思路,为其应用提供参考数据.  相似文献   

10.
面对宽幅地形测绘和空基大气测量等应用的需求,迫切需要发展能够适应机载平台的低功耗的小型化单光子探测系统.超导纳米线单光子探测器(SNSPD)因性能优异,已被应用到量子信息、深空通信和远程激光雷达等领域.然而,常规SNSPD所需低温系统的体积和重量均较大,不易于应用到机载平台.截至目前,国际上还未出现应用于机载平台的SNSPD的相关报道.本文设计并制备了工作温度为4.2 K的SNSPD.超导探测器芯片是光敏面积为60 μm×60 μm的四通道光子数可分辨器件,通过光束压缩系统耦合到直径200 μm的光纤,在温度为4.2 K时量子效率大于50%@1064 nm.最后,测试了单个通道的时间特性,在不同光子数响应的情况下得到了不同的时间抖动,其中四光子响应时的时间抖动最小,半高宽为110 ps.该工作不仅可支撑机载应用,而且对于推动发展通用的小型化SNSPD系统及其应用具有积极意义.  相似文献   

11.
We demonstrate a photon-counting chirped amplitude modulation(CAM) light detection and ranging(lidar) system incorporating a superconducting nanowire single-photon detector(SNSPD) and operated at a wavelength of 1550 nm.The distance accuracy of the lidar system was determined by the CAM bandwidth and signal-to-noise ratio(SNR) of an intermediate frequency(IF) signal. Owing to a short dead time(10 ns) and negligible dark count rate(70 Hz) of the SNSPD, the obtained IF signal attained an SNR of 42 d B and the direct distance accuracy was improved to 3 mm when the modulation bandwidth of the CAM signal was 240 MHz and the modulation period was 1 ms.  相似文献   

12.
We designed and fabricated a special doped niobium (Nb*) superconducting nanowire single-photon detector (SNSPD) on MgO substrate. The superconductivity of this ultra-thin Nb* film was further improved by depositing an ultra-thin aluminum nitride protective layer on top. Compared with traditional Nb films, Nb* films present higher T C and J C. We investigated the dependence of the characteristics of devices, such as cut-off wavelength, response bandwidth, and temperature, on their geometrical dimensions. Results indicate that reduction in both the width and thickness of Nb* nanowires extended the cut-off wavelength and improved the sensitivity. The Nb* SNSPD (50 nm width and 4.5 nm thickness) exhibited single-photon sensitivities at 1,310, 1,550, and 2,010 nm. We also demonstrated an enhancement in the detection efficiency by a factor of 10 in its count rate by lowering the working temperature from 2.26 K to 315 mK.  相似文献   

13.
The rapid development of superconducting nanowire single-photon detectors over the past decade has led to numerous advances in quantum information technology. The record for the best system detection efficiency at an incident photon wavelength of 1550 nm is 93%. This performance was attained from a superconducting nanowire single-photon detector made of amorphous WSi; such detectors are usually operated at sub-Kelvin temperatures. In this study, we first demonstrate superconducting nanowire single-photon detectors made of polycrystalline NbN with system detection efficiency of 90.2% for 1550-nm-wavelength photons at 2.1 K, accessible with a compact cryocooler. The system detection efficiency saturated at 92.1% when the temperature was lowered to 1.8 K. We expect the results lighten the practical and high performance superconducting nanowire single-photon detectors to quantum information and other high-end applications.  相似文献   

14.
The performance of superconducting nanowire single-photon detector (SNSPD) involving niobium nitride with the fan coupling antenna array is analyzed. The SNSPD has a high detection efficiency and counting rate. Hydrogen silsesquioxane and niobium nitride are filled in the gold grating deposited on the substrate in which the fan coupling antenna arrays are embedded. By changing the position of the fan coupling antenna array, the maximum area of optical intensity is obtained and the photon collection efficiency is increased by 26.5 times. The detection efficiency of SNSPD is improved without changing the detection speed. These parameters are important for designing a practical single-photon detector,  相似文献   

15.
We designed and developed a volume phase holographic (VPH) grism with high resolution and high efficiency in the near-infrared light domain (1550 nm) to be applied as a wavelength de-multiplexing device of a photonic network. In order to achieve both diffraction efficiency of over 80% and wavelength resolution of 0.08 nm, we newly designed and fabricated a VPH grism with high efficiency and high wavelength resolution in near-infrared wavelength region by sandwiching a VPH grating between prisms. An active feedback control technique was introduced to a two-beam interference exposure system, and we also applied it to a wavelength de-multiplexing device for a photonic network. Consequently, a VPH grism was successfully fabricated with diffraction efficiency of over 80% by employing the Bragg condition of 1550 nm at the incident wavelength from 1530 to 1570 nm, and high refractive index modulation of 0.047 was confirmed.  相似文献   

16.
超导单光子探测技术是基于超薄超导薄膜的非平衡态热电子效应的一种新型的单光子探测方法。超导单光子探测器(SNSPD)的计数率可达到GHz,时间抖动小于100ps,因而在未来量子通信系统中有着广阔的应用前景。介绍了NbN超导单光子探测器件的工作原理和器件超导性能测试系统;测试了超导单光子探测器件的电阻-温度、电流-电压等特性。并对测试结果进行了分析和讨论。  相似文献   

17.
Hou-Rong Zhou 《中国物理 B》2022,31(5):57401-057401
Superconducting nanowire single-photon detectors (SNSPDs) are typical switching devices capable of detecting single photons with almost 100% detection efficiency. However, they cannot determine the exact number of incident photons during a detection event. Multi-pixel SNSPDs employing multiple read-out channels can provide photon number resolvability (PNR), but they require increased cooling power and costly multi-channel electronic systems. In this work, a single-flux quantum (SFQ) circuit is employed, and PNR based on multi-pixel SNSPDs is successfully demonstrated. A multi-input magnetically coupled DC/SFQ converter (MMD2Q) circuit with a mutual inductance M is used to combine and record signals from a multi-pixel SNSPD device. The designed circuit is capable of discriminating the amplitude of the combined signals in accuracy of Φ0/M with Φ0 being a single magnetic flux quantum. By employing the MMD2Q circuit, the discrimination of up to 40 photons can be simulated. A 4-parallel-input MMD2Q circuit is fabricated, and a PNR of 3 is successfully demonstrated for an SNSPD array with one channel reserved for the functional verification. The results confirm that an MMD2Q circuit is an effective tool for implementing PNR with multi-pixel SNSPDs.  相似文献   

18.
单光子探测是一种量子极限光信号的检测技术,超导纳米线单光子探测器(Superconducting NanowireSingle-Photon Detector,SNSPD)作为一种新型的单光子探测技术,在量子通信等众多领域有着广阔的应用前景。SNSPD的动态电感直接决定了SNSPD的工作速度。文中对SNSPD动态电感的特性和测试方法做了详细的研究,成功实现了低温下SNSPD动态电感的测试,并对结果进行了分析处理和研究。利用BCS理论对动态电感随温度、偏置电流变化的特性进行分析计算,并与实际测量结果对比讨论,为未来如何降低SNSPD动态电感、提高其性能的研究工作提供了参考依据。  相似文献   

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