Large-area, free-standing gratings for atom interferometry produced using holographic lithography

Abstract

Interferometers based on matter waves promise orders-of-magnitude improvements in metrology over laser-based systems by virtue of the fact that the de Broglie wavelengths of atoms are about 104 times shorter. To date, the required matched set of four aligned gratings for such atom interferometers has been made using electron beam lithography and, as a result, such gratings suffer from a lack of spatial-phase coherence. We report on processes we have developed for fabricating free-standing gratings over large areas using conventional holographic lithography and achromatic holographic lithography to achieve spatial periods of 200 and 100 nm, respectively (i.e., nominal linewidths of 100 and 50 nm, respectively).