针对红外制导空舰导弹航路规划中的重要影响因素——攻击角，建立了航路点数量、相邻航路点间距、航路点转弯角和航路路程等约束条件模型；提出了最大攻击角的解析计算方法，并区分一个、两个和多个航路点等三种情况，运用几何学原理，分别给出了最大攻击角的定量计算模型。最后，对航路点数量、转弯角和导弹航程等因素影响下的最大攻击角进行了仿真计算。结果显示，最大攻击角随着航路点数量的增加而快速增大；航路点数量一定时，最大攻击角随着航路点转弯角的减小而增大；但应注意，攻击角的增加是以牺牲红外制导空舰导弹航程为代价的。

针对合成孔径雷达（Synthetic aperture radar，SAR）目标分类问题，提出基于最大熵准则的多视角方法。采用经典的图像相似度测度构建不同视角SAR图像之间的相关性矩阵，在此基础上分别计算不同视角组合条件下的非线性相关信息熵值。非线性相关信息熵值可分析多个变量之间的统计特性，熵值的大小即可反映不同变量之间的内在关联。根据最大熵的原则选择最优的视角子集，其中SAR图像具有最大的内在相关性。分类过程以联合稀疏表示为基础，对具有最大熵值的多个视角进行联合表示。联合稀疏表示模型同时处理若干稀疏表示问题，在它们具有关联的条件下具有提升重构精度的优势。根据不同视角求解得到的表示系数，按照类别分别计算对于选取多视角的重构误差，并根据误差最小的准则进行最终决策。文中方法可有效对多视角SAR图像样本进行相关性分析，并利用联合稀疏表示利用这种相关性，能够更好提高分类精度。采用MSTAR数据集对方法进行分析测试，通过与几类其他方法在多种测试条件下进行对比，结果显示了最大熵准则在多视角选取中的有效性和文中方法对SAR目标分类性能的优越性。

An experimental investigation of two-color polarization spectroscopy (TCPS) is presented based on the cesium 6S_1/2 – 6P_3/2 – 8S_1/2 (852.3 nm + 794.6 nm) ladder-type system in a room-temperature vapor cell. The dependency of line shapes of TCPS on the power of a 852.3 nm pump and a 794.6 nm probe laser is measured in detail, and we confirm that the linewidth of TCPS in a counter-propagating configuration between the pump and probe laser beams is obviously narrower than that of a co-propagating configuration, due to the atomic coherence effect. It is helpful for laser stabilization of the excited state transition using TCPS without frequency modulation.

A 1470 nm+852 nm two-color (TC) cesium (Cs) magneto-optical trap (MOT) with a 6S1/2-6P3/2-7S1/2 ladder-type system is proposed and experimentally investigated. To the best of our knowledge, it is the first report about the 1470 nm+852 nm Cs TC-MOT. One of the three pairs of the 852 nm cooling and trapping beams (CTBs) in a conventional Cs MOT is replaced with a pair of the 1470 nm CTBs. Thus, the TC-MOT partially employs the optical radiation forces from photon scattering of the 6P3/2 (F′=5) 7S1/2 (F′′=4) excited-state transition (1470 nm). This TC-MOT can cool and trap Cs atoms on both the red- and blue-detuning sides of the two-photon resonance. This work may have applications in cooling and trapping of atoms using inconvenient wavelengths and background-free detection of cold and trapped Cs atoms.

We demonstrate a magneto-optical trap (MOT) with counter-propagating two-color cooling beams in a cesium 6S1/2 6P3/2 8S1/2 (852.3+794.6 nm) atomic system. Based on the conventional MOT due entirely to the 852.3 nm cooling laser’s scattering forces, we replace one of the six 852.3 nm cooling beams with a 794.6 nm cooling beam. Our two-color MOT can efficiently cool and trap atoms from the red to blue detuning sides of two-photon resonance without pre-cooling. The technique is promising for the direct generation of correlated photon pairs in a two-color MOT based on diamond-configuration four-wave mixing.