On the production of diffraction gratings I. The copying of plane gratings

Abstract

The paper is the first of a series describing the development at the National Physical Laboratory of new methods of making, copying and testing diffraction gratings. It describes the development of a method devised by Merton (1950) for copying a plane grating by using a plastic pellicle to transfer the cast of the grating to a gelatine surface. It shows how to obtain such pellicles free from distortion and how to make optically flat gelatine surfaces. The diffracted wave-fronts of parent and replica respectively agree to a fraction of a fringe.