双Lloyd镜数字全息显微测量术

提出了一种双Lloyd镜数字全息显微测量技术.其基本思想是将Lloyd镜的共光束自干涉特性与双波长光学相位解包裹方法相结合,使用两个Lloyd镜调节参考光与物光夹角以形成共光束自干涉,从而获得一张双波长复合全息图,再通过角谱法再现得到每个波长对应的包裹相位,利用两波长的相位差求得解包裹后的相位图和三维高度分布图.采用532和632 nm两波长记录全息图,通过数值再现重构被测物体的振幅和相位信息.与标定值相比,实验值的误差小于5%,证明了该方法的有效性.

Digital holographic microscope employing dual-Lloyd’s mirror

We propose a digital holographic microscopy (DHM) setup employing a configuration with two Lloyd's mirrors, which is based on self-referencing and dual-wavelength optical phase unwrapping. We use two Lloyd's mirrors to fold the beam which does not exhibit sample structure and acts as the reference beam, returning onto itself to form a dual-wavelength hologram. Two wrapped phase images for every wavelength are reconstructed by angular spectrum method. Then the wrapped phase image and the three-dimensional profile image are acquired by dual-wavelength optical unwrapping method. In the experiment, we use two lasers of different wavelengths of 532 and 632 nm to record a hologram. Numerical methods are subsequently applied to reconstruct the hologram to enable direct access to both phase and amplitude information. The quantitative experimental results with dual-wavelength DHM involve a deviation less than 5% from the calibration values. The validity of this method is demonstrated.
Keywords：holographydual-wavelength digital holographyoptical phase unwrappingLloyd's mirror