Concurrent monitoring of zeroth-order and diffraction-order interference fringes for mosaicking echelle

A mosaicking method for echelles is proposed. The “zero-order” and diffraction-order interference fringes of the echelle can be imaged simultaneously on the detector using a mirror–echelle structure designed. The five-dimensional mosaicking errors are divided into two categories for elimination using the “zero order” and the diffraction order. During the experiments, adjustment devices for the mosaicking errors are installed on two echelles for these two categories to avoid mechanical coupling. As theoretical analysis, we follow the experimental steps to obtain a mosaicked echelle.