Revealing macrodefects in periodic structures of the transmission type in white light on the basis of shift of images

The possibility of revealing macrodefects in periodic structures of the transmission type in white light on the basis of shift of images of the structures under investigation is shown. A simple scheme of visualization of macrodefects on the basis of obtaining shifted images of structures by using a plane mirror placed behind the periodic structure is described. A method for revealing macrodefects in periodic structures with the possibility of increasing the sensitivity of measurements is proposed. The method is based on making a photograph of a periodic structure with subsequent optical processing of this structure and its photograph, which are optically conjugate and shifted with respect to each other. An increase in the sensitivity of this method is achieved owing to separation of complex conjugate orders of diffraction of light by the structure and its photograph. The methods proposed do not require using reference periodic structures. Experimental results of testing of the methods for visualization of macrodefects in cross-shaped metal grids are presented.