Resolving power of the Gaussian pupil optical lithography system beyond Rayleigh's limit of resolution

In order to obtain resolution higher than Rayleigh's limit of resolution ϵ/sub R/, we use Gaussian pupil which gives the diffraction intensity distribution with resolution ϵ/sub G/<ϵ/sub R//2, where ϵ/sub G/ is the half-width at half-maximum of the Gaussian function.