On the Applicability of Standard Resolution Targets in Quantitative Phase Imaging Based on Multi-angle Laser Illumination Digital Holographic Microscopy (DHM)

To research digital holography resolution enhancement a standard resolution target was used to calibrate the resolution of a digital holographic microscopy (DHM) system; however, the positive standard resolution target and negative target can indicate different resolution for the reflection DHM system. The reflection multi-angle illumination DHM system was built and the positive and negative standard resolution targets are tested, respectively. Comparing to the positive standard resolution target, the negative standard resolution target's interference fringes of the hologram are clearer, the values of the high frequency part of the frequency spectrum are larger, and the phase noises of the phase image are less; therefore, for reflectance DHM system, it is more suitable to test the negative standard resolution target. The reason of the result analysed from the reflectivity of the resolution target and the spectrum of the hologram is demonstrated. This study is of great significance to the measurement of microdevices with low reflectivity substrate, such as silicon dioxide based microfluidic devices.