Multibeam projection microinterferometer with an image amplifier

An experimental investigation was made of the principal properties of a multibeam projection microinterferometer with a copper-vapor image amplifier. The optical system and the operating principle of the microinterferometer are described. It is shown that the lower limit of the height of a microstructure which can be determined is less than 10 nm. If the edges of the microstructure are sharp, the upper limit can reach 5λ, where λ = 0.5782 μm is the wavelength of the radiation of the copper-vapor image amplifier.