共查询到20条相似文献,搜索用时 0 毫秒
1.
Phase diversity wavefront sensor is one of the useful tools to estimate the wavefront aberration, and it is often used as a wavefront sensor in adaptive optics system. However, the performance of the traditional phase diversity wavefront sensor is limited by the accuracy and dynamic ranges of the intensity distribution at focus and defocus positions of the CCD camera. In this paper, a modified phase diversity wavefront sensor based on a diffraction grating is proposed to improve the ability to measure the wavefront aberration with larger amplitude and higher spatial frequency. The basic principle and the optics construction of the proposed method are also described in detail. The noise propagation property of the proposed method is also analysed by using the numerical simulation method, and comparison between the diffraction grating phase diversity wavefront sensor and the traditional phase diversity wavefront sensor is also made. The simulation results show that the diffraction grating phase diversity wavefront sensor can obviously improve the ability to measure the wavefront aberration, especially the wavefront aberration with larger amplitude and higher spatial frequency. 相似文献
2.
自适应光学系统要求波前传感器能实现动态实时测量,曲率波前传感技术符合这一发展要求。一种新型的基于扭曲衍射光栅的曲率波前传感器在探测装置的实现方法方面具有较大优势,其波前重构已应用于光学度量。根据衍射光学理论,对其探测信号进行数值模拟,并利用Neumann边界条件的Green函数法对其波前重构进行数值模拟。结果表明:Green函数法归结为2矩阵相乘,计算速度快,达到实时重构要求; Green函数法对阶数不高的Zernike多项式重构效果较好;影响重构误差的主要因素是光强梯度的边界噪声。 相似文献
3.
针对相位光栅曲率传感器能够测量波前曲率在光瞳面上分布的特点,提出了一种采用整个空间分布的曲率信号来实现波前校正的算法。用曲率型变形镜影响函数的曲率信号在光瞳面上的分布来拟合待校正波前的曲率信号,采用最小二乘方法得到变形镜的控制电压,实现波前校正过程。数值模拟了一种41单元曲率型自适应光学系统采用该算法的波前校正过程。结果表明,对4至28阶Zernike像差体现了校正效果,对曲率为0的Zernike像差校正效果略好于曲率不为0的Zernike像差。与传统分区法的校正效果相比,整体法对Zernike像差的校正效果基本相当。整体法无需对光瞳面上的曲率信号进行与电极分布相同的分区,降低了对系统校准的要求。 相似文献
4.
5.
6.
用Hartmann-Shack(H-S)波前传感器可以准确测量穿过超声速流场的激光波面及其变化过程,进一步计算可以获得光束质心漂移、远场分布等数据。给出了H-S方法测量穿过超声速流场激光波面的原理,采用模式法进行了波前重构,计算了在几种流场条件下的激光波面像差特性PV值,RMS值和Zernike像差系数、Strehl比和环围能量曲线等。结果表明,H-S法可以很好地反映流场建立、稳定和结束过程中Zernike像差的变化。比较无流场和给定参数的超声速流场,激光穿越后产生的最明显的像差变化为离焦和低阶像散的增大。在相同流场参数下,无模型时光束质量好于有模型时光束质量。 相似文献
7.
8.
9.
10.
11.
相位差技术可以直接利用两幅或多幅图像的强度信息,重构出波前相位信息和目标清晰图像,具有光路简单、成本较低、适用于扩展目标等优点,在望远镜的系统像差检测和目标图像重建方面得到了大量应用。相位差波前探测的关键在于求解非线性代价函数的最优化问题,需要避免陷入局部极值并降低计算时间,才能满足动态变化波前实时探测的需求。同时在重建目标清晰图像时,通常需要做正则化和去噪处理,来提高重建图像的质量。本文主要介绍相位差技术的基本原理,以及近年来的研究进展,并对该技术未来的发展进行了展望。 相似文献
12.
用Hartmann-Shack(H-S)波前传感器可以准确测量穿过超声速流场的激光波面及其变化过程,进一步计算可以获得光束质心漂移、远场分布等数据。给出了H-S方法测量穿过超声速流场激光波面的原理,采用模式法进行了波前重构,计算了在几种流场条件下的激光波面像差特性PV值,RMS值和Zernike像差系数、Strehl比和环围能量曲线等。结果表明,H-S法可以很好地反映流场建立、稳定和结束过程中Zernike像差的变化。比较无流场和给定参数的超声速流场,激光穿越后产生的最明显的像差变化为离焦和低阶像散的增大。在相同流场参数下,无模型时光束质量好于有模型时光束质量。 相似文献
13.
14.
针对附加像差为离焦的情况,对焦面位置误差、离焦量误差、图像对准误差以及图像噪声等因素带来的波前传感误差进行了数值模拟,并给出了确定焦面位置、对准焦面图像和离焦面图像、精确计算分光比、确定离焦量以及处理图像噪声的方法。使得传感结果的均方根误差分别由0.088 8λ,0.059 0λ,0.128 4λ,4.170 6λ,0.152 6λ降为0.002 1λ,0.002 1λ,0.002 1λ,0.002 1λ,0.029 2λ。结果表明:这些方法可以有效地减小传感误差,大大提高了传感精度,为相位差法的实际应用提供了重要的技术支持。 相似文献
15.
相因子判断法分析菲涅耳波带片的衍射场 总被引:1,自引:0,他引:1
基于波前相因子判断法,并考虑到波带片孔径的影响,揭示了波带片的衍射场所含基元成分及各成分在衍射场的积分表达式,并导出了沿轴的衍射场振幅分布公式及沿轴的振幅分布曲线,得到多个实焦斑的横向半值线宽和轴向半值线宽公式.本研究为波带片作为一种光学元件提供了一理论基础. 相似文献
16.
针对附加像差为离焦的情况,对焦面位置误差、离焦量误差、图像对准误差以及图像噪声等因素带来的波前传感误差进行了数值模拟,并给出了确定焦面位置、对准焦面图像和离焦面图像、精确计算分光比、确定离焦量以及处理图像噪声的方法。使得传感结果的均方根误差分别由0.088 8λ,0.059 0λ,0.128 4λ,4.170 6λ,0.152 6λ降为0.002 1λ,0.002 1λ,0.002 1λ,0.002 1λ,0.029 2λ。结果表明:这些方法可以有效地减小传感误差,大大提高了传感精度,为相位差法的实际应用提供了重要的技术支持。 相似文献
17.
18.
将模式偏置法与全息多重存储法波前传感器原理联系起来,通过研究模式偏置波前传感器的输出响应特性,间接得到全息模式波前传感器的运行规律。对模式偏置波前传感器进行理论分析与总结,并建立简化模型,针对若干阶Zernike像差,通过数值模拟对理论结果进行验证。模拟结果显示:传感器输出信号与各种类型待测像差系数有不同的变化关系,这与理论分析结果吻合。以散焦模式像差为例,利用两个相位型空间光调制器动态加载模式像差,分别在入射光波中引入待测像差和偏置像差,探测焦平面光斑强度变化。实验结果表明:以峰值光强作为焦平面光强分布的信息提取方式,进而得到正负偏置光斑的光强差和归一化光强差,这比在小孔光阑上进行积分更简单有效。 相似文献
19.
Spectral diagnosis of radiation from laser plasma interaction and monochromation of radiation source are hot and important topics recently. Grating is one of the primary optical elements to do this job. Although easy to fabricate, traditional diffraction grating suffers from multi-order diffraction contamination. On the other hand, sinusoidal amplitude grating has the nonharmonic diffraction property, but it is too difficult to fabricate, especially for x-ray application. A novel nonharmonic diffraction grating named random position rectangle grating(RPRG) is proposed in this paper. Theoretical analysis and experiment results show that the RPRG is both higher order diffraction suppressing and not difficult to fabricate. Additionally, it is highly efficient; its first order absolute theoretical diffraction efficiency reaches 4.1%. Our result shows that RPRG is a novel tool for radiation diagnosis and monochromation. 相似文献
20.
A multi-point diffraction strain sensor (MDSS) was developed earlier by us for strain measurement with variable sensitivity and measurement range using a microlens array. The technique is now extended to measure both tilt and non-uniform strain with a sensitivity of 0.41 mε/pixel and 4.7 mrad/pixel. The validation was made through comparison of the strain measured using MDSS with that by a micro-Moiré interferometer incorporated with Gabor filtering method, while the tilt is compared with derivatives of the surface profile measured by a confocal microscope. 相似文献