共查询到20条相似文献,搜索用时 31 毫秒
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T. Nishikawa M. Yokota S. Nakamura Y. Kadoya M. Yamanishi I. Ogura 《Photonics Technology Letters, IEEE》1997,9(2):179-181
Photon reabsorption effect on the transfer efficiency /spl beta//sub t/ of half-wavelength semiconductor microcavities was investigated by examining the excitation intensity dependence of the output light intensity. It is shown that /spl beta//sub t/ increases under intense excitation, and approaches to over-all spontaneous emission coupling coefficient /spl beta//sub 0/, as a result of the elimination of photon reabsorption. The results clearly demonstrate that the photon reabsorption is the predominant mechanism of the suppression of /spl beta//sub t/ at weak excitation, especially in the case of half-wavelength high-Q cavities. 相似文献
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针对新型单光子线性APD器件获得信息维度多、灵敏度高的特点,提出了一种基于单光子线性APD的微弱回波信号距离信息提取算法。首先利用微弱信号的泊松分布特性对回波信号进行建模,随后对每纳秒内的回波光子数进行统计,利用与脉宽等宽的距离窗进行滑窗求和,将最大值位置作为信号脉冲接收时刻,进而反算距离信息。设计了跟踪前的目标搜索策略和稳定跟踪后的距离门匹配算法,有效降低了背景光干扰和计算资源消耗,在回波光子数分别为200、10、5个时分别获得了100、9993、9658的计算正确率。对单光子量级信号设计了脉冲积累算法,单个光子信号回波的计算正确率为995。同时对静止目标通过算法迭代实现了信噪比为0dB甚至负dB的信息提取,对003个光子信号回波探测的计算正确率为961。仿真结果表明该算法可以综合应用单光子线性APD的强度信息以及单光子灵敏度,实现了在极限灵敏域下的距离信息提取。 相似文献
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N. Asli M. I. Vexler I. V. Grekhov P. Seegebrecht S. E. Tyaginov A. F. Shulekin 《Semiconductors》2004,38(9):1030-1035
Recombination luminescence spectra of tunnel Al/SiO2/p-Si MOS structures have been studied experimentally. A mathematical reconstruction of these spectra taking into account the loss by photon reabsorption is carried out. For the first time, the experimental data are presented in absolute units (W eV?1). A relationship is shown between the shape of the spectrum and the energy of injected electrons, which is defined by the applied voltage. The rate of energy loss by photon emission has been estimated. The effect of the oxide degradation on the luminescence characteristics of MOS structures is considered. 相似文献
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扩展目标光子测距回波特性及误差研究 总被引:1,自引:0,他引:1
光子测距具有灵敏度高,探测距离远的特点,目标形状和姿态对光子测距的影响不可忽略。针对扩展平面、球面和非球面三种典型目标,建立了扩展目标光子探测回波概率分布模型,推导出不同倾斜角下混有时空分布的光子回波概率分布一般方程。实验表明,扩展平面的光子回波概率分布与数值计算结果一致。理论仿真分析了扩展目标的光子回波概率分布特性,讨论了光子测距误差与扩展目标类型和倾斜角间的变化规律。结果表明:平均回波光子数为3.9,目标处激光光斑半径为0.2m,倾斜角小于20°时不同扩展目标间的光子测距误差小于1.23mm;光子测距误差随着目标倾斜角的增大逐渐增大,且扩展平面目标测距误差受倾斜角影响最大。 相似文献
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为了研究激光-等离子体相互作用过程中的光子加速(光子频率上移),采用数值模拟方法进行了理论计算和数值计算验证,取得了光子加速的重要计算机模拟结果。结果表明,等离子体激光相互作用过程中的光子频率上移与所用的激光脉冲形式和脉冲宽度有关,存在最佳脉冲宽度和脉冲上升宽度,还存在等离子体电子密度上限。这一结果对进一步研究激光等离子体粒子加速有帮助。 相似文献
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报道了单光子探测条件下的法拉第反常色散滤波器(FADOF)滤波特性的实验结果。测量结果表明,工作在D2共振线的Rb原子780nm法拉第反常色散滤波器的翼谱透射率为28%,滤光带宽为0.7GH2,以及最小可探测激光功率为0.16pW/cm^2。由于使用了单光子探测器测量法拉第反常色散滤波器物理参数的方法,极大地提高了实验测量的探测灵敏度。通过实验数据分析,给出了相关的讨论。在日光情况下,如果使用这种780nm Rb法拉第反常色散滤波器代替干涉滤波片,将极大地降低背景光噪声和减少误码率,使得在单光子水平的激光通信更接近于实用。 相似文献
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De Neve H. Blondelle J. Baets R. Demeester P. Van Daele P. Borghs G. 《Photonics Technology Letters, IEEE》1995,7(3):287-289
This paper describes the design of substrate emitting microcavity LED's and a comparison of experimental results with modeling results. The modeling is based on a simulation tool which accounts for guided modes, quantum well reabsorption and photon recycling. The overall quantum efficiencies of λ/2 and λ cavities both with a 60% and a 90% reflecting DBR mirror are compared and a good qualitative correspondence is found between theory and experiment. The maximum theoretical overall quantum efficiency for the considered structures is expected to be around 14%, whereas the best experimental value amounts to 10.2% 相似文献
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光子筛作为一种衍射光学元件,具有较大的色散,不适用于宽光谱成像。光子筛的焦距随着入射波长的增大而减小,而正的折射透镜焦距随着入射波长的增大而增大。应用了折衍混合方法进行光子筛消色差的设计。该设计利用二者相反的色散特性,在光子筛的一侧紧密放置一平凸透镜,从而实现光子筛的消色差设计。并针对可见光光谱进行了设计,分析表明该方法能够实现消色差,且具有一定校正二级光谱的能力,消色差波长与中心波长处焦距相对误差为0.33%,成像光谱带宽为20nm。与普通单个光子筛相比,该方法有效拓宽了光子筛的成像光谱范围。与使用波带片的折衍混合系统相比,聚焦光斑更小。 相似文献
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电磁波轨道角动量(OAM)量子态指构成电磁波的每个电磁波量子均具有OAM,是涡旋电磁波的重要形态之一。在微波波段,这种电磁波量子称为“涡旋微波量子”。涡旋微波量子与传统平面波微波量子具有不同的物理特性,针对传统吸波材料具有强反射系数,造成雷达散射截面积(RCS)增加,并提升目标回波的接收信号功率和检测概率,是对抗基于吸波材料的隐身目标之利器。该文提出了基于OAM量子态的涡旋微波量子雷达,给出了基本物理架构和数学模型,借助量子电动力学(QED)从理论上分析了涡旋微波量子的高回波功率特性,并通过实验验证了理论分析的正确性。在收发端均采用相同极化方式下,与传统平面波雷达相比实验中回波功率提高约9 dB。同时,配合典型雷达工作参数进行了仿真,明确了涡旋微波量子雷达在接收功率和检测概率等性能指标上的提升,进一步展现了涡旋微波量子针对吸波材料的反隐身能力。 相似文献
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Matsuda T. Ohzone T. Odanaka S. Yamashita K. Koike N. Tatsuuma K. 《Semiconductor Manufacturing, IEEE Transactions on》2003,16(2):233-238
Hot-carrier-induced photoemission of subquarter-micron n-MOSFETs is analyzed using a specially designed test structure, which has a wide channel width of 2.0 mm for sufficient photoemission intensity. Since the test structure consists of parallel-connected unit MOSFETs and photoemission images are uniform, it can be estimated that the measured spectra are the same as those from unit MOSFETs. The relation between photon counts and photon energy suggests that photon energy has a Boltzmann distribution, exp(-h/spl nu//kT/sub e/). The electron temperature T/sub e/ calculated from the photon emission spectrum takes a minimum value at the channel length of 0.23 /spl mu/m. If T/sub e/ is related to device reliability, it suggests the possibility that the device structure optimized for a certain channel length may not be optimum for other channel length devices. 相似文献
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Spinelli A. Ghioni M.A. Cova S.D. Davis L.M. 《Quantum Electronics, IEEE Journal of》1998,34(5):817-821
Experimental tests have been carried out for characterizing the performance of a new single-photon avalanche diode. The detector is specifically designed for picosecond time-correlated single photon counting, aiming to obtain a time response free from the tail effects and/or secondary bumps observed in all other available single-photon detectors. The experimental results confirm that an unprecedented ultraclean response is attained, with full width at half maximum (FWHM) of 35 ps, full width at a thousandth of the peak count of 214 ps, together with a photon detection efficiency of 35% around 580-nm wavelength 相似文献
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光子探测技术是弱光探测领域的热点,介绍了SPM(硅光电倍增管阵列)探测器件的工作原理、基本结构、性能特点,为了验证SPM探测器的光子探测性能以及光子分辨能力,利用高速跨导放大器设计了SPM光子探测电路,并进行了光子探测实验研究。根据实验结果可以得出结论,SPM探测器具有较好的光子分辨特性。 相似文献
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H.W. Choi C.W. Jeon M.D. Dawson 《Photonics Technology Letters, IEEE》2004,16(1):33-35
The fabrication and performance of an InGaN light-emitting diode (LED) array based on a microring device geometry is reported. This design has been adopted in order to increase the surface area for light extraction and to minimize losses due to internal reflections and reabsorption. Electrical characteristics of these devices are similar to those of a conventional large-area LED, while the directed light extraction proves to be superior. In fact, these devices are found to be more efficient when operated at higher currents. This may be attributed to improved heat sinking due to the large surface area to volume ratio. The potential applications of these devices are also discussed. 相似文献
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By means of simple mathematical methods, typical properties of the quantum dynamics in the Jaynes-Cummings model are discussed. The methods used allow a clear physical interpretation in the sense of an ensemble average and permit an investigation of the influence of the initial photon distribution width on collapse and revivals. Results obtained by a more sophisticated treatment provide corrections which are on the order 1/√N 0 for N 0>>1 where N 0 is the average photon number. The time evolution of the electric field strength and the photon distribution are also studied 相似文献
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基于线阵光子计数探测器模块,实现了碲锌镉探测器的光子计数应用。研究了大剂量X射线下碲锌镉探测器的计数性能,发现碲锌镉光子计数探测器根据其典型计数性能可分为两类:C1,C2。分析了这两类典型的光子计数探测器的计数性能与X射线能谱响应特性、前放脉冲信号上升时间以及碲锌镉探测器缺陷水平的内在联系,在此基础上研究了温度对C2类碲锌镉光子计数探测器计数性能的影响规律,升高温度可以抑制探测器的极化失效,提高计数率,且当温度升高至33℃时,探测器计数性能可得到显著改善。最后利用线阵光子计数探测器模块,获得了不同温度下C2类碲锌镉光子计数探测器的多能区成像结果,升高温度可以显著增加其图像衬度,提高成像质量。该研究为通过控制外部条件提高碲锌镉光子计数探测器性能提供了有效手段。 相似文献
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Michael Saliba Wei Zhang Victor M. Burlakov Samuel D. Stranks Yao Sun James M. Ball Michael B. Johnston Alain Goriely Ulrich Wiesner Henry J. Snaith 《Advanced functional materials》2015,25(31):5038-5046
Organic–inorganic metal halide perovskite solar cells have emerged in the past few years to promise highly efficient photovoltaic devices at low costs. Here, temperature‐sensitive core–shell Ag@TiO2 nanoparticles are successfully incorporated into perovskite solar cells through a low‐temperature processing route, boosting the measured device efficiencies up to 16.3%. Experimental evidence is shown and a theoretical model is developed which predicts that the presence of highly polarizable nanoparticles enhances the radiative decay of excitons and increases the reabsorption of emitted radiation, representing a novel photon recycling scheme. The work elucidates the complicated subtle interactions between light and matter in plasmonic photovoltaic composites. Photonic and plasmonic schemes such as this may help to move highly efficient perovskite solar cells closer to the theoretical limiting efficiencies. 相似文献