半导体纳米颗粒电子的超快弛豫过程

为了研究在飞秒激光作用下半导体纳米颗粒的超快动力学过程,建立了一个带表面态的三能级结构的载流子弛豫简化模型,得出各能级的电子速率方程.利用数值模拟方法模拟出各能级电子密度和差分吸收率随时间的变化情况,得知由于吸收截面的变化,差分吸收谱会有一个超快的变化过程.并将模拟结果与FanxinWu等人的实验结果相比较,其曲线特征基本一致.说明该模型有一定的合理性.     

Imaging theory and resolution improvement of two-photon confocal microscopy

The nonlinear effect of two-photon excitation on the imaging property of two-photon confocal microscopy has been analyzed by the two-photon fluorescence intensity transfer function derived in this paper. The two-photon fluorescence intensity transfer function in a confocal microscopy is given. Furthermore the three-dimensional point spread function (3D-PSF) and the three-dimensional optical transfer function (3D-OTF) of two-photon confocal microscopy are derived based on the nonlinear effect of two-photon excitation. The imaging property of two-photon confocal microscopy is discussed in detail based on 3D-OTF. Finally the spatial resolution limit of two-photon confocal microscopy is discussed according to the uncertainty principle.     

Integrated tunable optofluidics filter based on the plasmonic structure with double side-coupled cavities

A novel method is presented to enhance the resonant transmission contrast ratio in metal-insulator-metal（MIM）sidecoupled-cavity waveguide.The finite difference time domain（FDTD）method is used to simulate and study the optical properties of the filter based on double side-coupled cavities structure with optofluidics pump system（OPS）.This system provides a flexible way to change wavelength in the optical filter.In the numerical simulation,the resonant wavelengths from 1000 nm to 1550 nm are analyzed.We find that the double side-coupled cavities structure with OPS has higher onresonance transmittance and better wavelength selectivity than the single side-coupled cavity structure with OPS.     

量子保密通信用准单光子源的研制

量子保密通信是一种以基本粒子的量子力学性质为依据，在理论上证明是绝对安全的密钥分配技术。其绝对安全性引起了国内外的高度重视。要实现量子保密通信有两大关键技术——单光子脉冲技术和单光子探测技术．单光子是量子保密通信的基础，如果通信信道中含有两个或多个光子，则窃听者就可能截取多余的光子进行检测而不被知晓，从而     

光声光谱技术在测量光谱响应特性方面的应用

用光声光谱技术测量光电探测器的相对光谱响应特性,以高灵敏度的光声池(池内装有吸收系数约为1的碳黑)作为参考探测器,具有较好的波长无选择性。用碳黑监测光源功率,减少光源功率起伏误差。采用二次测量归一化方法避免了分束器的影响。实验测得了比较准确的相对光谱响应特性曲线,为研究光电探测器的特性提供了一种可行的方法。     

旋转双光楔折射特性与二维扫描轨迹的分析

 为实现旋转双光楔二维扫描的可控操作,利用几何光学和光的标量衍射理论,对双光楔的折光特性进行了数学分析。研究发现：绕固定轴以不同角速度旋转的双光楔可等效为一个折射棱角和主截面都变化的单光楔。以该双光楔系统作为衍射屏,对通过双光楔的光束在观察面的衍射光场分布作了理论分析,得到了夫琅和费衍射下,光束经转动双光楔在像平面上的衍射光斑随转角变化的规律：光斑的横坐标与两光楔转角正弦值的差成正比,纵坐标与两光楔转角余弦值的和成正比。     

Vacuum Rabi Oscillation of an Atom without Rotating-Wave Approximation

We have investigated vacuum Rabi oscillation of an atom coupled with single-mode cavity field exactly, and compared the results with that of the Jaynes-Cummings （J-C） model. The results show that for resonant ease, there is no Rabi oscillation for an atom. For small detuning and weak coupling case, the probability for the atom in excited state oscillates against time with different frequencies and amplitudes from that of the J-C model. It exhibits that the counter-rotating wave interaction could significantly effect the dynamic behaviour of the atom, even under the condition in which the RWA is considered to be justified.     

Practical non-orthogonal decoy state quantum key distribution with heralded single photon source

Recently the performance of the quantum key distribution （QKD） is substantially improved by the decoy state method and the non-orthogonal encoding protocol, separately. In this paper, a practical non-orthogonal decoy state protocol with a heralded single photon source （HSPS） for QKD is presented. The protocol is based on 4 states with different intensities. i.e. one signal state and three decoy states. The signal state is for generating keys; the decoy states are for detecting the eavesdropping and estimating the fraction of single-photon and two-photon pulses. We have discussed three cases of this protocol, i.e. the general case, the optimal case and the special case. Moreover, the final key rate over transmission distance is simulated. For the low dark count of the HSPS and the utilization of the two-photon pulses, our protocol has a higher key rate and a longer transmission distance than any other decoy state protocol.     

Analysis of performance and optimum configuration of two-stage semiconductor thermoelectric module

In this paper, the theoretical analysis and simulating calculation were conducted for a basic two-stage semiconductor thermoelectric module, which contains one thermocouple in the second stage and several thermocouples in the first stage. The study focused on the configuration of the two-stage semiconductor thermoelectric cooler, especially investigating the influences of some parameters, such as the current I1 of the first stage, the area A1 of every thermocouple and the number n of thermocouples in the first stage, on the cooling performance of the module. The obtained results of analysis indicate that changing the current I1 of the first stage, the area A1 of thermocouples and the number n of thermocouples in the first stage can improve the cooling performance of the module. These results can be used to optimize the configuration of the two-stage semiconductor thermoelectric module and provide guides for the design and application of thermoelectric cooler.     

对称型正负交替一维光子晶体超窄带滤波器

构造了(AB)N1(BA)N2对称型正负折射率交替一维光子晶体,并利用传输矩阵法进行数值模拟,研究了这种正负折射率交替一维光子晶体的能带结构与各参数之间的关系.结果表明:当两种材料的光学厚度相同时,该结构光子晶体比传统的光子晶体的带隙大得多,且在主禁带内有极窄的透射带.并利用此透射带,设计了一种在红外波段1550nm窗口3dB带宽可以做到0.000001nm以下,窗口内透过率接近100%的超窄带滤波器.该结构的光子晶体可以用作超窄带滤波器,有望在光通信超密集波分复用系统中获得广泛应用.