【作者】 吴青林；

【导师】 韩正甫； 卫国； 郭光灿；

【作者基本信息】 中国科学技术大学 ， 通信与信息系统， 2008， 博士

【摘要】 物理学、化学和生物学等众多基础学科领域的检测技术追求更小的时间尺度,因而也就需要实现更高的时间精度。如何实现纳秒甚至皮秒级精度的时间测量是高速电子学的热点之一。本文对高精度时间信号的处理和检测技术进行了研究,设计出一套高精度时间甑别电路并将其应用于量子信息技术等领域,包含以下几个方面的内容:1.针对远程量子密钥分配系统需要亚纳秒级时间同步的需求,详细分析了自由空间量子密钥分配系统同步误差的来源,指出了空间光信号的传输时间精度判定误差主要来源于大气湍流等引起的光强抖动,首次提出了利用恒比甑别法降低同步误差的设想,并研制出对应的恒比甑别时间同步系统。通过野外的实地测试,在1.5公里单向传输时实现了95ps时间同步精度,往返3公里时间精度达到119ps,达到国际同类工作的先进水平;2.设计并完成了红外单光子探测器的研制过程中的高速微弱信号的放大、甄别和窄脉冲成型等工作,解决了红外单光子探测器研制中的部分难题;3.首次提出将半导体红外单光子探测技术应用于拉曼光谱测量并搭建了测试系统。这项技术将拉曼激发波长平移到近红外波段,避免了短波激发的强荧光信号淹没弱拉曼信号的问题,使得荧光材料的拉曼测量成为可能;4.利用红外单光子探测器的窄门控技术,提出采用门扫描模式测量荧光寿命的方法并在实验上予以实现。与传统的荧光寿命测量方法相比,不仅将测量波长拓展到近红外波段,而且解决了常开模式单光子探测器时间积累暗计数的问题,可实现更高灵敏度的时间谱测量;对铒镱共掺磷酸盐玻璃的荧光发射光谱和荧光寿命测量证实了该系统的实用性,为红外波段荧光光谱分析提供了一种新的测量手段。更多还原

【Abstract】 Precise time measurement is important in fundamental research field such as physics, chemistry and biology. It is always been a hinder for high speed electronics to realize time measurement in nanosecond and picosecond scale. In this thesis high speed electonics for accurate time pick-up is studied. The whole work consists of the following contents:1. The synchronization error of free space quantum key distribution (QKD) has been studied in detail. We deduced that in long distance free space QKD, the synchronization error originates from the intensity fluctuation due to atmospheric turbulence. We have introduced the constant fraction discrinator (CFD) to decrease the synchronization error. We built a high precision CFD and applied it to the synchronization testing system. The synchronization error of a 1.5km one way transimission is 95ps. When the distance extends to 3km, the error is slightly increased to 119ps with CFD.2. We have conmpleted circuit design for high speed amplifier, discriminator and narrow pulse generating etc., which are important parts for infrared single photon detector (SPD).3. We have brought the infrared SPD into raman spectroscopy researching and built a infred raman testing system. When excited with ultraviolet and visiable light, the Raman signal is fully buried by the strong fluorescence. By using infred light source as excited light, the fluorescence emission can be avoided.4. With the advantage of infrared SPD, We can measure the fluorescence lifetime with gated mode. Not only the measurement wavelength is extended to near infrared, but also the problem of dark count accumulation of traditional SPD is solved. Compared with the classic fluorescence lifetime measurement technique, this new device can provide a brandnew method to infrad fluorescence analyzing. In practice, the fluorescence emission spectrum and lifetime of Erbium dropped laserglass are measured with this new method, which confirm its feasibility.更多还原