Optical elements with ultrahigh spatial-frequency surface corrugations

TLDR

The paper investigates optical elements fabricated by holographically recording an ultrahigh spatial‑frequency pattern in a photoresist mask and transferring it into quartz via reactive ion etching. The method uses holographic recording of an ultrahigh spatial‑frequency pattern in a photoresist mask, followed by reactive ion etching to imprint the pattern onto the quartz surface. The resulting elements are environmentally durable, easily replicated, achieve diffraction efficiencies above 85 %, exhibit low broadband reflection (≤0.035 %) at normal incidence, produce artificial birefringence for wave‑plate use, and are especially valuable for UV and IR applications lacking durable antireflection coatings or transparent birefringent materials.

Abstract

In this paper we discuss the properties of optical elements fabricated by holographically recording an ultrahigh spatial-frequency pattern in a photoresist mask followed by reactive ion etching to transfer this pattern into the surface of a quartz substrate. Such optical elements are environmentally durable, potentially easy to replicate, and exhibit diffraction efficiencies in excess of 85%. In addition, two other properties are reported for the first time. Such elements at normal (0°) incidence are antireflective, with broadband reflection coefficients as low as 0.035%. Also, the elements exhibit artificially produced birefringence making them useful as wave plates. These results may be particularly significant in the UV and IR, where damage-resistant antireflection coatings and transparent birefringent materials may not exist.