基于4f系统的Gabor同轴相移数字全息

Gabor In-Line Phase-Shifting Digital Holography Based on 4f System

传统Gabor同轴全息中的直透参考光波与衍射物光波空间重叠,因而无法实现相移干涉。针对这一问题,提出了一种在Gabor同轴全息中引入相移的数字全息方法。根据空间频谱域中不同频率分量空间分离的特点,通过在4f系统的频谱面上采用纯相位空间光调制器对空间频谱的零频分量(直透参考光波)单独进行相位调制实现相移干涉,然后利用相移干涉算法得到再现像。理论分析和实验结果表明,基于4f系统的Gabor同轴相移数字全息方法可以在保留Gabor同轴全息光路简单、受环境振动和空气扰动影响小、对光源相干性和记录器件空间分辨率要求较低等优点的基础上,消除直流项和共轭像的影响,提高了再现像质量。

In traditional Gabor in-line holography, direct passing reference wave and diffracted object wave overlap in space, thus it is unable to realize phase-shifting interferometry. A method to realize Gabor in-line phase-shifting digital holography is presented. Based on the characteristic that different spatial frequency components are separate in the spatial frequency domain, a spatial light modulator is placed in the spatial spectrum plane of the 4f system to introduce phase-shift to the zero-frequency component of spatial frequency spectrum, and the corresponding phase-shifting algorithm is utilized to obtain the reconstructed image. Theoretical analysis and experimental results show that the proposed method can improve the quality of reconstructed image while retaining the original advantages of conventional Gabor in-line holography at the same time.