大偏转角液晶光栅相控阵波前测量方法研究

Liquid crystal grating, as a kind of optical phased array, has been used in laser radar system, satellite communication system and other photoelectric systems to realize agile beam steering. In order to control directional beam quality, the wavefront of liquid crystal grating phased array needs to be tested and the wavefront distortion needs to be analyzed to correct it in real time. The special dramatically-changed wavefront contour of the liquid crystal grating makes wavefront measurement difficult. At present, the maximum deflection angle of liquid crystal grating phased array is becoming more and more large. It causes more severe ups and downs of wavefront, so wavefront measurement becomes more difficult. To promote our country's development of phased array technology, it is necessary to explore measurement method of the high frequency wavefront of liquid crystal grating phased array.It has been proposed to measure the wavefront of large deflection angle liquid crystal grating phased array by means of a novel quadrilateral radial shearing interferometer with beam direction changing device and a new method of single diffraction order inversion.The main research contents of this project include the impact of the wavefront distortion of large deflection angle liquid crystal grating phased array on the grating diffraction field, the high frequency wavefront reconstruction algorithm and development of a device for measuring wavefront of phased array instantaneously.

液晶光栅作为一种光学相控阵被应用在激光雷达、卫星通信等系统中，可以实现激光束的灵活偏转。而要对定向光束的质量进行控制，就需要对液晶光栅相控阵的波前进行测量，分析波前畸变的情况，以实现波前实时校正。液晶光栅出射波前特殊的剧烈变化的轮廓使得对其测量非常困难。目前，液晶光栅相控阵正向着大偏转角方向发展，波前起伏会更加剧烈，对测量提出了更高的要求。因此有必要探索液晶光栅相控阵高频变化波前的测量方法，以促进我国相控阵技术的发展。本项目提出了用带光束变向装置的新型四边形径向剪切干涉仪，采用新的单一衍射级反演法来测量大偏转角液晶光栅相控阵的出射波前。主要研究大偏转角液晶光栅相控阵波前畸变对衍射光场的影响, 研究高频波前重构算法以及研制相控阵波前实时测量装置。

液晶光栅作为一种光学相控阵被应用在激光雷达、卫星通信等系统中，可以实现激光束的灵活偏转。而要对定向光束的质量进行控制，就需要对液晶光栅相控阵的波前轮廓进行测试。本项目主要研究了大偏转角液晶光栅相控阵波前畸变对衍射光场的影响，用matlab仿真技术模拟了在不同情况下衍射光场光强分布情况；研究了高频波前重构算法,提出用单一衍射级反演法来测量大偏转角液晶光栅波前轮廓；对相控阵波前实时测量装置进行研制，提出了用带光束变向装置的四边形径向剪切干涉仪来测量大偏转角液晶光栅相控阵波前，研制出了口径10mm×10mm的剪切干涉仪；研究了径向剪切干涉波前重构算法,并分析重构精度；实测了液晶光栅相控阵的静态相位分布及偏转波前轮廓，可为液晶光栅器件的性能分析及加载电压方案提供依据。