同步相移数字全息综述(特邀)

A Comprehensive Review on Parallel Phase-shifting Digital Holography(Invited)

相移数字全息技术将相移技术与数字全息技术相结合,为微观物体的三维形貌和折射率分布检测提供了一种快速、无损、高精度手段。与离轴数字全息相比,相移数字全息采用同轴光路,可以充分利用CCD相机的空间带宽积。然而,传统相移数字全息需要依次记录多幅不同相移量全息图,才能消除零级像和共轭像,再现出无混叠的相位/振幅图像。同步相移又称瞬时相移,可在同一时间得到多幅不同相移量的干涉图样,克服普通相移干涉不能实时观测的缺点。介绍了相移的概念和实现方式,基于多CCD记录、像素掩膜、平行分光的三种同步相移技术,对同步相移数字全息在生物医学、流场测量、表面形貌测量、微纳器件检测等领域的应用进行综述,为从事同步相移数字全息技术及其应用研究的学者提供有益参考。

Phase-shifting Digital Holography(PSDH),which combines phase-shifting technology with digital holography,provides a fast,non-invasive,and high-precision approach for the three-dimensional morphology or refractive index distribution of microscopic objects.Compared with the off-axis digital holography,the phase-shifting on-axis digital holography makes full utilization of Spatial-bandwidth Product(SBP)of the CCD camera.The conventional phase-shifting digital holography needs to records multiple phase-shifting holograms in a step-by-step manner,from which the artifact-free phase and amplitude images of a sample can be reconstructed.To enhance the imaging speed of PSDH,parallel phase-shifting technique(or simultaneous phase-shifting technique)was proposed,with which multiple phase-shifting holograms can be obtained at the same time.In this paper,the concept and implementation of phase-shifting technologies are introduced firstly.Then,three different approaches of parallel phaseshifting,which are based on multiple CCDs,pixelated phase-mask,and parallel beam-splitting,are reviewed.Eventually,the applications of parallel PSDH in the biomedical field,air/liquid flow visualization,surface topography,micro-/nano-scale device inspection are introduced.