旋转激光扫描无源多靶点定位方法

由于旋转激光扫描测量系统采用的是有源式收发分体的仪器架构,因此其易受到工业现场复杂测量条件的制约。针对系统现场适应性受限的问题,提出了一种基于旋转激光扫描的单站式无源多靶点定位方法。在所提方法中,将多个角锥棱镜作为无源待测靶点。通过构建非球面反射接收模型实现了信号发射端与接收端的结合,并分析比较了该测量模式下的信号延时。此外,建立了多靶点光信号匹配机制以实现无源多靶点交会定位。最后,在工作空间测量定位系统平台上进行了实验验证。结果表明,所提方法在10 m测量范围内的三个方向上均能实现亚毫米级的定位精度,有效提高了旋转激光扫描测量系统在复杂测量环境中的适应性。     

斜程湍流大气中部分相干艾里光束的偏振特性研究

偏振是激光通信中保密编码的重要参数,研究斜程湍流大气中的偏振特性对激光通信具有重要意义.利用广义惠? 更斯-菲涅尔原理和偏振-相干统一理论,推导了无衍射的部分相干艾里高斯光束在斜程湍流大气传输中的偏振度解析式,详细研究了湍流参数、相干长度、天顶角、截断因子和分布因子对偏振度的影响.研究结果表明:与水平湍流相比...     

Dynamical behavior and propagation characteristic of partially coherent sinh-Airy beams in oceanic turbulence

By introducing the hyperbolic sine function to Airy beam, the dynamic behavior and propagation characteristics of partially coherent sinh-Airy beams in oceanic turbulence are studied using approximate analytical intensity expression. The influence of sinh modulation parameter, coherence length and ocean parameters on intensity evolution, beam width and kurtosis parameter is mainly discussed. The results show that a non-zero sinh modulation parameter presents not only the insensitivity to oceanic turbulence, but a smaller beam width. Furthermore, it also improves kurtosis parameter. These findings bring advantages in signal reception for long distance. In addition, a larger relative intensity of temperature or salinity fluctuations, mean square temperature dissipation rate, or a smaller dissipation rate of turbulence kinetic energy is more liable to increase beam width, or decrease intensity and kurtosis parameter of partially coherent sinh-Airy beams. The results provide an opportunity for improving signal reception of underwater communication or target detection by Airy beams or their groups.     

Spectral properties of partially coherent chirped Airy pulsed beam in oceanic turbulence

Spectral shifts and spectral intensities of partially coherent chirped Airy pulsed(PCCAP) beams propagating through oceanic turbulence are studied, where spectral properties of partially coherent chirped Gaussian pulsed(PCCGP) beams are also compared. The effects of optical parameters and oceanic turbulence parameters on spectral shifts at different observation positions are mainly discussed. It is shown that the spectral shift of PCCAP beam is richer than that of PCCGP beam, and there exists some critical positions for PCCAP beams where the spectral red-shift reaches its maximum. The spectral red-shift increases with increasing chirped parameter, correlation length or decreasing pulse duration. However, the increasing of spectral red-shift is accompanied by increasing dissipation rate of turbulence kinetic energy in unit mass liquid or decreasing relative intensity of temperature and salinity fluctuations, mean square temperature dissipation rate. A physical explanation of rapid spectral transition is also made.     

部分相干啁啾光学相干涡旋晶格在生物组织湍流中的平均光强与光谱位移

本文研究了部分相干啁啾光学相干涡旋晶格在生物组织湍流中的平均光强和光谱位移,详细探讨了单色光场中的光学晶格结构和多色光场中的光谱快速跃迁特性.研究表明:在生物组织湍流中,光束从具有涡旋核的环形结构演变为具有暗区的周期阵列结构,最后呈类高斯图样.尽管晶格常数能调制光束结构,但它不影响光束在生物组织湍流中的光谱跃迁行为.光...