【作者】 董华芳；

【导师】 曾和平；

【作者基本信息】 华东师范大学 ， 光学， 2008， 硕士

【摘要】 先进的探测技术在人类探索自然的进程中起着至关重要的作用。作为灵敏度达到量子极限的红外单光子探测,不仅对于未来长距离量子信息网络的构建具有重要的应用价值,同时也是很多红外物理技术领域,如:激光雷达、制导、传感等的核心技术。鉴于目前广泛使用的可见光波段和红外波段的单光子探测器在探测性能上的显著差异,引发了对红外单光子的跨波长探测的设想,并且该设想的可行性已经获得了理论和实验的证实。本文以实用的红外单光子探测为研究目的,围绕高效、稳定、灵敏三个主要技术目标,论述了我们对1.55μm和1.06μm两个重要而典型的红外波段单光子进行的上转换探测。1.讨论了用频率上转换方法实现红外单光子量子态转移的可行性以及达到完全量子态转移所需要的实验条件,包括泵浦光强度、相位匹配条件、空间重合条件等。2.以二极管泵浦的固体激光器为基础,利用单向激光腔内泵浦的方案实现了高效、稳定的1.55μm红外单光子上转换探测。探测效率达到了96%,而稳定性的标准误差仅为1.9%,并且在此基础上进行了可调谐频率上转换的实验探索。3.以更加便携、灵敏的高效单光子探测为目标,在1.55μm的锁模光纤激光器和掺铒光纤放大器的基础上,用脉冲泵浦的方案实现了1.06μm超灵敏的红外单光子上转换探测。由于使用了单光子能量低于信号光子能量的泵浦光源,探测灵敏度获得了极大的提高,得到了大于12000的信噪比。更多还原

【Abstract】 Advanced detection technology plays an important role in the process of human being’s exploration into the natural world. The detection of infrared single photons-the ultimate limit in detector sensitivity- is the core technology and of great application value for future long-distance quantum information network construction as well as many infrared physics technology, such as lidar, guidance and sensor etc. While the performance of current widely-used infrared single-photon detectors are much worse than the ones for visible light, and this significant difference has inspired us with an assumption: should we up-convert the infrared single-photons to the visible region? During the past decade, the feasibility of this assumption has been proved theoretically and experimentally.Our purpose is to establish a practical infrared single-photon detection system, so efficiency, stability and sensitivity are most emphasized in our research. This dissertation documents our main results on single-photon frequency up-conversion detection at 1.55μm and 1.06μm respectively, which are both important and typical wavelength in infrared region.1. We discussed experimental feasibility for quantum-state preserving frequency translation with single-photon frequency up-conversion and its experimental conditions for near-unity up-conversion, including pumping intensity, phase matching and space coincidence conditions.2. Based on diode-pumped solid-state laser, we realized efficient and stable single-photon detection at 1.55μm by intra-cavity frequency up-conversion in a unidirectional ring laser, with the efficiency and standard deviation of stability being 96% and 1.9% respectively. And with this experimental setup we also made exploration on tunable frequency up-conversion.3. Aiming at more portable and sensitive infrared single-photon detection, we obtained single-photon detection at 1.06μm with ultra-low dark counts, which was pulse pumped by an amplified passively mode-locked fiber laser at 1.55μm. With the energy of the pump photon lower than that of the signal photon, the sensitivity of this long-wavelength-pumping setup was greatly enhanced, with its signal-to-noise ratio larger than 12000.更多还原