Direct laser fabrication of dense microlens arrays in semiconductor-doped glass

A direct laser writing technique in semiconductor-doped glasses is used to fabricate microlens arrays with fill factors exceeding the close-packing limit for circular microlenses. This is achieved by both structural and thermal interactions between adjacent lenses during fabrication, which result in the formation of microlenses shaped in accordance with the translational symmetry of the array. The effect of nearest-neighbor interaction on various time scales is studied and shown to be critical to the distortions observed.