"In this work the effects of the modification on the optical microscope pupil, and their applications are presented. Two variations of the pupil are analyzed, in the first one the consequences of placing a vortex type phase filter in the pupil plane of the microscope is studied. The phase filter is a quantized version of an optical vortex; this modifies an optical microscope into a phase contrast microscope which can be used in the quantification of the measured phase by the rotation of the discrete vortex. This first modification in the pupil plane leads the extension of the phase vortex filter into two areas in optical metrology; speckle metrology and the creation of a new interferometer. For the second study case, the pupil of the microscope was expanded creating a super resolution optical microscope. The developed microscope was based on the projection of structured light onto the sample, generating a synthetic pupil microscope twice the size as the original, which lets the passage of high frequency information that previously was restricted by the optical transfer function microscope. The built microscope was implemented for the measurement and characterization of nano-structures formed on metal surfaces with ultra-short laser pulses."