An optical system for producing electromagnetic radiation with localized increases in irradiance or radiance at the system output includes a first optical mask containing localized regions for producing controlled modifications of phase delays and/or amplitude attenuations and located within the input plane of said optical system. The system also includes at least a single optical component with positive optical power located after the input plane and at least one additional optical mask located after the optical component at non-conjugate locations with respect to the input plane of the system. The additional optical mask contains localized regions for producing controlled modifications of phase delays. Locally increased radiation distributions are produced at the system output.