近年来，携带扭曲相位的部分相干光束因其独特的性质受到广泛关注。引入一种同时携带扭曲相位和具有特殊空间关联结构的部分相干矢量光束，即径向偏振扭曲矩形多高斯-谢尔模光束，推导了该光束通过ABCD光学系统后的交叉光谱密度矩阵元解析表达式，并研究了它的归一化光强分布、光谱相干度和光谱偏振度的演化特性。研究结果表明，当无扭曲相位时，径向偏振矩形多高斯-谢尔模光束的光强由源平面的空心圆环轮廓逐渐演变成矩形平顶轮廓。相较而言，径向偏振扭曲矩形多高斯-谢尔模光束所携带的扭曲相位不仅会引起光束光斑的旋转，还会引起传播过程中光束的相干度和偏振度的一系列变化。该研究结果为扭曲相位实现新型矢量结构光束的调控提供一定的理论指导，在光束整形、光学微操纵和自由空间光通信等领域有着潜在的应用。

基于扩展小波树理论和多任务贝叶斯模型,提出了彩色图像自适应压缩采样方法。根据扩展小波树结构中父子系数和兄弟系数的关系,对彩色图像中红、绿、蓝三通道图像分别进行了自适应压缩采样。利用彩色图像三通道间的相关性和多任务贝叶斯模型,分别处理了采样得到的三通道高频小波系数,并重构融合得到彩色图像。研究结果表明,当采样次数为600、采样率为14.6%时,利用所提方法得到的彩色重构图像的峰值信噪比均大于27 dB,色差均值最小,色差值也趋于稳定,图像色调保持着较好的一致性和稳定性。

In the context of correspondence ghost imaging, we utilize the correlation coefficients to separate the reference detector speckle patterns into positive and negative correlated parts. A positive image and a negative image of the object are obtained by averaging over corresponding speckle patterns. The visibility and contrast-to-noise ratio of the positive image are discussed, and it is found that the latter will reach a maximum by averaging over a little less than half of the total number of reference speckle patterns.

The random phase errors of the optical carriers are discussed and controlled for passive millimeter-wave sparse aperture (PMMW SA) upconversion imaging. A two-channel model is set up for analyzing characteristics of the phase errors, and an active optical control technique based on stochastic parallel gradient decent algorithm (SPGD controller) is proposed to calibrate the phase errors. To demonstrate the feasibility of the SPGD controller, simulations are performed and an experimental system with a two-channel fiber array is set up. Simulation and experiment results show that the SPGD controller can effectively and rapidly compensate the phase errors of the optical carrier, and the accuracy of the phase control is sufficient for imaging systems.

By using a feedback-stabilized fiber Mach-Zehnder interferometer (MZI) with a PZT-based phase shifter, a novel method for measurement of laser coherence length is demonstrated based on pulses interference. Experimental results show that the coherence length is closed to that measured by the commercial optical spectrometer, and the partial coherence phenomenon is observed. Our scheme can measure not only the high-coherence laser but also low-coherence pulses, which is widely used in coherent laser measurement and application.

A set of two-dimensional (2D) binary codes are created by the calculation of the speckle contrast in line scan laser display system. According to the 2D binary code, phase plates are fabricated by etched glass or photoresist with different thicknesses corresponding to the code. It is introduced on the intermediate image plane to reduce speckle in laser based line scan display system. The experimental results show that the phase plate with the 2D binary code of order 5 can successfully reduce speckle contrast to 17.5%.

In this letter, we use quantum description and the Gaussian state to study reflective ghost imaging with two classical sources, and to provide their expressions. We find that the reflective ghost imaging of a rough-surfaced object, using Gaussian-state phase-insensitive or classically correlated phase-sensitive light, can be expressed in terms of the phase-insensitive or phase-sensitive cross-correlations between the two detected fields, including a background term. Moreover, reflective ghost imaging with two classical Gaussian-state lights is shown to have similar features as spatial resolution and field of view.