Exploring the capabilities of Digital Holography as tool for testing optical microstructures

A demonstration of the capabilities of Digital Holography (DH) in microscope configuration is presented for inspecting and qualifying optical microstructures. Different structures with dimensions ranging from hundreds to few tens of microns are investigated, analyzed and characterized by DH showing that the technique is suitable either for liquid as well as polymeric microlenses. Thanks to the numerical reconstruction of the complex wavefields, we show that DH is able to retrieve not only the morphology of each single structure element but also to furnish accurate information on all the changes (spontaneous or induced) occurring during the inspection time, such as the curvature variation of liquid microlenses or the wavefront distortion.