超导纳米线单光子探测器热弛豫时间特性研究

超导纳米线单光子探测器（SNSPD）可以实现量子极限灵敏度的电磁信号探测。光子探测动态过程中重要的一环是超导纳米线热点能量如何通过衬底和环境介质进行弛豫，它决定了SNSPD的最高工作速度。本项目将研究薄膜材料及薄膜/衬底界面因素等对热弛豫时间的影响，阐明热弛豫时间决定性机理；深入理解热弛豫时间与器件Latching特性关联机制，提出减小热弛豫时间、提高SNSPD计数率的方法。基于以上研究内容，结合单、双温度模型与热电反馈机制，阐明热点弛豫动力学过程，加深对器件探测机理的理解。

Superconducting nanowire single photon detectors (SNSPD) have the ability to detect radiation intensities at the quantum limit. Absorption of a photon results in creation of an energetic quasi-particle. The substrate and environment interactions with the quasi-particle redistribute this energy and thermalize the electrons back to the substrate temperature. The rates of this process is defined by the hotspot relaxation time of the quasi-particle, which determined the maximum operating rate of SNSPD. In this project, the superconducting materials and the film/substrate interface will systematically investigated to identify the main contributing factors to the hotspot relaxation time. The studies will help us deeply understand the relationship between thermal relaxation time and device latching characteristics. This study is of highly important scientific significances and application values in promoting high rate SNSPD devices. Based on the above research, the hotspot relaxation dynamics will be clarified combined with the single and dual temperature models and the thermoelectric feedback mechanism, which provide insight into the device detection mechanism.