2μm波段激光器的发展状况

讨论了产生2μm激光的两种方式,结合最新的相关文献分别对直接泵浦的2μm全固态激光器和2μm光学参量振荡器(OPO)的发展状况进行了详细的论述,并指出了2μm激光的应用前景。     

叶绿素紫外吸收特性的分析研究

鉴于光合作用对人类生存和发展的极其重要的地位,本文选取其关键载体——叶绿素进行其光谱的分析研究。在理论分析的基础上,使用WGD-8A型多功能组合光谱仪测量并分析了叶绿素的紫外吸收特性。结合实验结果和前人的研究成果,得出叶绿素在紫外波段281nm和312nm处有较强的吸收峰,紫外线对于光合作用有促进作用的结论,并提供了一种测量叶绿素含量的方法。     

Experimental investigation on chaos generation in erbium-doped fiber single-ring lasers

In this paper,the chaotic behaviors in an erbium-doped fiber(EDF) single-ring laser(EDFSRL) are investigated experimentally by using the loss modulation method.An electro-optic modulator(EOM) made of LiNbO 3 crystal is added to the system.Thus,by changing the modulation voltage and the modulation frequency of the EOM,the freedom of the EDFSRL system is increased.The chaotic characteristics of the system are studied by observing the time series and the power spectra.The experimental results indicate that the erbium-doped fiber single-ring laser system can enter into chaos states through period-doubling bifurcation and intermittency routes.     

Spontaneous emission from a microwave-driven four-level atom in an anisotropic photonic crystal

The spontaneous emission from a microwave-driven four-level atom embedded in an anisotropic photonic crystal is studied. Due to the modified density of state(DOS) in the anisotropic photonic band gap(PBG) and the coherent control induced by the coupling fields, spontaneous emission can be significantly enhanced when the position of the spontaneous emission peak gets close to the band gap edge. As a result of the closed-loop interaction between the fields and the atom,the spontaneous emission depends on the dynamically induced Autler–Townes splitting and its position relative to the PBG.Interesting phenomena, such as spectral-line suppression, enhancement and narrowing, and fluorescence quenching, appear in the spontaneous emission spectra, which are modulated by amplitudes and phases of the coherently driven fields and the effect of PBG. This theoretical study can provide us with more efficient methods to manipulate the atomic spontaneous emission.     

All solid-state sum-frequency generation of 1.12-W continuous-wave laser at 588 nm

A new resonator design for doubly resonant continuous-wave(CW)intracavity sum-frequency mixing (SFM)is reported.1.12 W of coherent radiation at 588 nm is generated by mixing 1062-nm Nd:GdVO_4 laser and 1319-nm Nd:YAG laser.The optical-to-optical conversion efficiency is up to 3.7%.     

综合孔径雷达中激光源的工作频率

本文以综合孔径雷达的线性调频信号为出发点、利用取样定理讨论了综合孔径雷达的激光源的脉冲间隔Ｔ，并估计了它的数量级。     

Second-order cumulants ghost imaging

Ghost imaging (GI) is a technique to retrieve images by correlating intensity fluctuations. In this Letter, we present a novel scheme for GI referred to as second-order cumulants GI (SCGI). The image is retrieved from fluctuation information, and resolution may be enhanced compared to traditional GI. We experimentally performed SCGI image reconstruction, and the results are in agreement with theoretical predictions.     

基于图像融合的优化重构计算鬼成像

针对计算鬼成像采样过程中由于外界影响而出现的物体信息缺失问题,将小波分析应用于计算鬼成像系统中,同时在此系统中引入图像融合方法,构建一种基于图像融合的计算鬼成像系统,对此问题进行了仿真模拟与实验研究。并对结果进行了分析,结果显示此系统可以有效恢复待测物体信息、提高成像质量,相较于传统的计算鬼成像系统更加适用于实际应用环境。     

Hyperchaotic behaviours and controlling hyperchaos in an array of RCL-shunted Josephson junctions

This paper deals with dynamical behaviours in an array composed of two resistive-capacitive-inductive-shunted (RCL-shunted) Josephson junctions (RCLSJJs) and a shunted resistor. Numerical simulations show that periodic, chaotic and hyperchaotic states can coexist in this array. Moreover, a scheme for controlling hyperchaos in this array is presented by adjusting the external bias current. Numerical results confirm that this scheme can be effectively used to control hyperchaotic states in this array into stable periodic states, and different stable periodic states with different period numbers can be obtained by appropriately choosing the intensity of the external bias current.