Dammann grating array generators in amorphous silicon nitride

The authors give expressions for the power spectrum of a Dammann grating and present some advances in optimisation of the grating structure by stochastic algorithms. They then proceed to their experimental results in the fabrication of these elements in silicon nitride. Conventional photolithographic and electron-beam lithographic techniques are employed to construct the amplitude mask, which is converted into a phase grating using contact copying and chemical etching of the silicon nitride thin films