Abstract

A low order diffractive structure has a period Λ of the same magnitude as the incident wavelength (λ), $\Lambda \approx \mathcal{O}(\lambda )$, and thus admits only a few $(\mathcal{O}(1))$ propagating orders. An important subclass is defined by Λ < λ, for which only zero order propagates, and includes antireflective (”moth-eye”) structures, form birefringent phase plates, wire grid polarizers, and resonant guided wave filters. An example lying in the broader class is represented by the outer zones of a fast $(\tilde{f}/1)$ Fresnel phase lens, where Λ ≈ 2λ.

© 1996 Optical Society of America