Dammann gratings as integratable micro-optical elements created by laser micronanofabrication via two-photon photopolymerization

Dammann gratings, as beam splitters and coherent signal generators, were produced in a short fabricating cycle by femtosecond laser fabrication via two-photon photopolymerization. These holograms that each generated 2x2, 3x3, 4x4, 5x5, and 6x6 spot sources in the fan-out demonstrated diffraction efficiency of 36%, 25%, 29%, 52%, and 49%, respectively, comparable with the theoretical values. This work shows the promising prospect of femtosecond laser fabrication in compatibly manufacturing various micro-optical devices including Dammann gratings and their integrated systems.