【作者】 胡诗杰；

【导师】 吴健；

【作者基本信息】 电子科技大学 ， 光学， 2009， 博士

【摘要】 本文主要对全光路像差校正自适应光学技术和双变形镜自适应光学技术两方面作了全面而系统的理论研究和实验验证。自适应光学对光束大气传输波前畸变校正时,要求系统必须能同时校正激光束自身像差和大气湍流扰动造成的像差,并且能够同时有效地克服出射系统的制造误差、重力变形、光学元件工作过程的受热变形以及光路内部气体扰动的影响,得到接近衍射极限的输出激光光束。常规自适应光学系统仅能有针对性地校正其中一部分,而全光路像差校正自适应光学系统可以实现全光路像差的探测与校正。全光路像差校正自适应光学技术与常规自适应光学技术相比,不仅具有全光路像差校正的特点,而且可以提高系统的集成性和可靠性。论文首先阐述了光波在介质中的传播规律,然后在此基础上,详细推导了全光路像差校正自适应光学系统的工作过程,明确了出射信标经全系统校正后,到达目标的是角锥棱镜阵列本身像差的远场光斑,这个像差是系统的原理性误差。随后,提出了一套波前校正器全光路像差校正自适应光学系统和两套波前校正器全光路像差校正自适应光学系统的两种工作方式,它们分别是:“使用两束标准平行光分别标定共模哈特曼传感器”和“使用两种信标光之一的标准光标定共模哈特曼传感器”。在“使用两束标准平行光分别标定共模哈特曼传感器”工作方式中,全系统校正后到达目标的远场光斑与标定光的光束质量相关,在“使用两种信标光之一的标准光标定共模哈特曼传感器”工作方式中,全系统校正后到达目标的远场光斑与角锥棱镜阵列本身的像差相关。然后根据两种工作方式标定哈特曼传感器的繁简程度,认为“使用两束标准平行光分别标定共模哈特曼传感器”是一种耗时且耗力的工作方式,“使用两种信标光之一的标准光标定共模哈特曼传感器”可以在系统光路中随时对其标定,是一种节省时间的优选工作方式。因为全系统校正后的残差与角锥棱镜阵列的像差有关,所以论文对角锥棱镜阵列的像差进行了相应分析,认为影响角锥棱镜阵列像差的主要因素是综合角误差,这种综合角误差将导致角锥棱镜阵列像差的高阶化,因此控制单个角锥棱镜的综合角误差是减少角锥棱镜阵列像差的关键因素。论文从仿真和实验的角度,验证了对于0.6328μm波长的系统,单个角锥棱镜的综合角误差在1″左右时,角锥棱镜阵列的像差可以忽略不计。论文还分析了角锥棱镜阵列与哈特曼传感器的误差匹配问题,认为角锥棱镜阵列与哈特曼传感器必须严格对准,才能保证哈特曼传感器探测的准确性,从而保证系统校正的有效性。除此之外,论文还从工程应用的角度,分析了一套波前校正器全光路像差校正自适应光学系统和两套波前校正器全光路像差校正自适应光学系统采用的数据融合方法,前者可以采用直接斜率数据差分融合方法,后者可以采用把两套波前校正器探测的像差各自交给两套波前校正器校正的方法,不需要进行数据差分融合。最后成功实现了全光路像差校正自适应光学系统的室内闭环实验。论文研究的另一方面是双变形镜自适应光学技术。目前,在功率不断提高的激光器、天文观测、人眼像差校正、惯性约束聚变(Inertial Confinement Fusion)等领域,自适应光学要校正的像差可能同时包含大尺度低阶像差和小尺度高阶像差。这些像差对变形反射镜提出了较高要求,要求变形反射镜需要同时具有大行程和高空间频率两个特征。但是由于变形镜加工工艺等原因造成的物理限制,要求同一个变形镜同时具有较大行程和高空间频率是非常苛刻的要求。因此论文采用了双变形镜自适应光学技术,即在一套自适应光学系统中,采用两个变形镜对待校正像差进行校正,其中的一个变形镜是大行程低空间频率变形反射镜,另一个是高空间频率变形反射镜。但是由于系统中存在的两个变形反射镜均具有校正像差的功能,如果两个变形镜的解耦不好,可能造成校正过头或校正紊乱。因此论文提出了两种双变形镜的解耦算法,分别是分离模式系数校正算法和限定校正算法,论文对这两种校正算法均作了详细的理论推导和数值仿真;两种校正算法中,通过对离焦限定和像散限定的仿真,证明两个变形镜可以各司其职,大行程变形镜可以只校正大行程的低阶像差,高空间频率变形镜可以只校正除低阶像差以外的其他像差。最后,根据实际变形反射镜的驱动器由于材料和加工等原因造成的响应不一致,论文进一步作了详细的理论推导。最终用实验证明了系统中的两个变形反射镜可以按照期望分别校正大的低阶像差和相对较小的高阶像差,同时也验证了系统的校正效果,双变形镜自适应光学系统可以把大约10.6倍衍射极限的开环远场光斑校正到4.8倍衍射极限,这与采用双变形镜自适应光学系统中的高空间频率变形镜的常规自适应光学系统的校正效果相当。更多还原

【Abstract】 The principle and workings of the adaptive optics system for all path aberration correction and the double deformable mirrors (DMs) adaptive optics system are studied theoretically, numerical simulation and experiment are also conducted in this dissertation.Adaptive Optics guarantees the beam quality of laser projecting system, atmospheric turbulence compensation, correction of any disturbance and fabrication error. But conventional adaptive optics system can only correction one of them. The adaptive optics system for all path aberration correction is the new way to fulfill the correction of them all.The adaptive optics system for all path aberration correction is a new direction of adaptive optics technology. Apart from the all path aberration correction, highly integration and reliability lie in this system. Based on the previous research, the principle, error resulting from the principle and workings of the adaptive optics system for all path aberration correction are deeply studied theoretically and experimentally.According to the theory of wavefront propagating in optics medium, the principle of the adaptive optics system for all-path aberration correction was analyzed in detail, and the principle error of this system was clear, which is that the aberration on aim is the aberration of the retroreflector array. Based on the principle and the principle error of this system, two kinds of workings of adaptive optics for all path aberration correction are proposed, one is calibraiting two wavefront sensors using two normal parallel beam respectively, the other is calibrating two wavefront sensors using one of two normal parallel beam. While using the first working, the farfield on aim is the aberration of the normal parallel beam after adaptive optics correct the aberration. While using the second working, the farfield on aim is the the abeeration of the retroreflector array after adaptive optics correct the aberration. According to the operation of two working, we think that the second wording is the best method.The residual error after the adaptive optics correct the aberration is connected with the aberration of the retroreflector array, so the aberration was analyzed in this dissertation. The main factor of aberration of the retroreflector array is the all angle error, which will make the aberration of the retroreflector array be high order. In order to reduce the aberrtion of the retroreflector array, we must control the all angle error of the single retroreflector. In this dissertation simulation and experiment of the aberration of the retroreflector array were achived. The result indicates while the all angle error of the single retroreflector is 1", the aberration of the retroreflector array can be neglected.Meanwhile the error matching between the retroreflector array and wavefront sensor was analyzed in this dissertation. In order to guarantee the precision of the wvefront sensor detecting wavefront and the effect of the system, the error must be zero between the retroreflector array and wavefront sensor.Then the data fusion methods for single wavefront corrector AO system and double wavefront correctors AO system are analyzed theoretically. The result indicates that the direction slope data fusion can be use in the single wavefront corrector AO system for all-path aberration correction, and the data fusion can not be use in two wavefront correctors AO system for all-path aberration correction. At last a close-loop experiment of the system is realized successfully.Now in many fields, such as high power laser, correction of aberration of human being’s eyes, and Inertial Confinement Fusion(ICF), large scale low order aberration and small scale high order aberration may lie in the aberration to be corrected by adaptive optics system simultaneously. This kind of aberration requires the deformable mirror in adaptive optics have large stroke and high spatial frequency simultaneously. But it is very difficult that the the deformable mirror in adaptive optics have large stroke and high spatial frequency simultaneously. So double DMs adaptive optics technology was proposed in this dissertation, in which one DM’s stroke is large and another’s spatial frequency is high. Double DMs adaptive optics technology aims to correct the aberration with large scale low order aberration and small scale high order aberration simultaneously. It is not necessary that there are large stroke and high spatial frequency in single DM. Two kinds of decoupling algorithm of two DMs, that is separating model coefficient correction algorithm and confined correction algorithm, are presented. Two kinds of algorithms are deduced in detail, and numerical simulation is gived. Defocus limitation and astigmatism limitation in confined correction algorithm are simulated respectively. At last experiments were achived in this dissertation. The result indicates that two deformable mirrors can correct the large scale low order aberration and high order aberration respectively.更多还原