Simulating multilevel diffractive optical elements on a spatial light modulator.

Multilevel diffractive optical elements (DOEs) offer a solution to approximate complex diffractive phase profiles in a stepwise manner. However, while much attention has focused on efficiency, the impact on modal content in the context of structured light has, to our best knowledge, remained unexplored. Here, we outline a simple theory that accounts for efficiency and modal purity in arbitrary structured light produced by multilevel DOEs.