Simultaneous exposure and development technique for making gratings on positive photoresist

Abstract

A simultaneous exposure and development technique for forming diffraction gratings and recording holograms in positive photoresist is described. This technique not only reduces the exposure time significantly, but is also able to produce gratings with deep grooves and sharp ridges. With the photoresist placed in a liquid‐filled prismlike container, the smallest period obtainable by this method is reduced by a factor equal to the index of refraction of the liquid.