基于位相变更的非相干数字全息自适应成像

菲涅耳非相干数字全息作为一种非扫描的三维成像技术具有其独特的优势,但其成像过程中会受到各种像差的影响,导致成像分辨率、再现像的质量降低.为了解决这一问题,可以结合适当的自适应光学技术对波前像差进行探测和校正.位相变更是一种基于两幅具有已知位相差的强度图像实现波前探测和像差校正的技术.本文发展了基于位相变更的非相干数字全息自适应成像技术,不需要引入引导星,利用全息记录过程中的两幅相移全息图,实现波前像差的探测.本文给出了所发展技术的数值仿真和实验结果,结合位相变更算法求解出系统像差的位相分布,将像差的共轭位相加载到光瞳面上,在全息图记录的同时校正像差,从而提高重建像的质量.

Adaptive imaging by incoherent digital holography based on phase change

Fresnel incoherent correlation holography (FINCH) is a unique scanning-free three-dimensional imaging technique which enables holograms to be created from incoherent light illumination. However, the image quality is inclined to be destroyed by various optical aberrations, in the practical application of microscopic imaging. In order to solve this problem, some kinds of adaptive optics are combined with imaging technologies to detect the distorted wavefront and compensate for the aberrations. Phase diversity is an image-based adaptive optics method where two intensity images with a certain phase difference are used for wavefront sensing. In this paper, we develop an adaptive imaging technique by Fresnel incoherent digital holography combined with phase diversity (PD-FINCH). Two recorded phase-shift holograms are applied to wavefront sensing, and the phase of aberration is further extracted by phase diversity reconstruction algorithm. The compensation phase is uploaded on SLM in turn, thus the aberrations are corrected while recording holograms. Both the simulation and experimental results verify the validity of phase diversity in FINCH. All the results show the improvement of reconstructed image quality after wavefront aberration compensation.