A Doublet Microlens Array for Imaging of Biological Micron-size Objects

We propose a novel fluidic assembly-based microfabrication approach for obtaining low-cost, high numerical aperture (NA), doublet microlens arrays. The proposed doublet architecture consists of glass microspheres trapped on a predefined array of silicon microholes and covered with a thin polymer layer. An array of ~56 μm in diameter microlenses with a numerical aperture of ~0.495 were fabricated using this approach. We demonstrated magnified, brightfield as well as fluorescent image formation of micron-size objects directly on a CCD sensor using such a microlens array. The proposed microlens array can be readily employed for applications involving imaging of biological micron-size objects.