Interference method for mosaicking echelles using double-angle incident light and a mirror-echelle structure

A method of eliminating echelle mosaicking errors using a single-interferometer system combined with a mirror-echelle structure and double-angle incident light is proposed. Coplanar and in-plane mosaicking errors are, respectively, removed using interference fringes at zero order and diffraction order, and double-angle incidence light is exploited to erase the longitudinal offset. Two mirror-echelle structures, both with aluminum reserved for a mirror on the echelle plane to receive the double-angle incident light, are designed. The relationship between mosaicking error and the optical path difference is established. The evolution of the interference fringe pattern of mosaicking process is simulated, and a mosaicking experiment is then conducted following the simulation.