Visually testing the dynamic character of a blazed-angle adjustable grating by digital holographic microscopy

We employed digital holographic microscopy to visually test microoptoelectromechanical systems (MOEMS). The sample is a blazed-angle adjustable grating. Considering the periodic structure of the sample, a local area unwrapping method based on a binary template was adopted to demodulate the fringes obtained by referring to a reference hologram. A series of holograms at different deformation states due to different drive voltages were captured to analyze the dynamic character of the MOEMS, and the uniformity of different microcantilever beams was also inspected. The results show this testing method is effective for a periodic structure.