A system for performing an Additive Manufacturing fabrication process on a powdered material forming a substrate, the system comprising: a diode array for generating an optical signal sufficient to melt or sinter a powdered material of the substrate; a mask for receiving the optical signal generated by the diode array, the mask forming a liquid crystal polarization rotator, the liquid crystal polarization rotator including a liquid crystal module and a polarizer, wherein the liquid crystal module operates to receive and to rotate a first portion of the optical signal passing therethrough while allowing a second portion of the optical signal to pass therethrough without being rotated, and wherein the polarizer, which comprises a polarizing mirror, operates to reject by reflecting one of the first or second portions of the optical signal received from the liquid crystal module, and thus to prevent the one of the first or second portions from reaching the substrate, while the polarizer allows the other one of the first or second portions of the optical signal to reach the substrate, the liquid crystal module of the mask having a plurality of pixels arranged in a two dimensional pattern that are individually controlled to enable the mask to mask off one or more selected areas of a specific layer of the powdered material of the substrate, and wherein the mask absorbs substantially no optical energy from the optical signal; and at least one processor controlling an output of the diode array and assisting in controlling operation of the mask such that only selected one of the pixels are controlled to enable portions of the optical signal passing through the liquid crystal polarization rotator to be rotated to thus form the first portion of the optical signal; and wherein the diode array is configured to provide a power density of at least about 10kW/cm 2 at a two percent duty cycle. a diode array for generating an optical signal sufficient to melt or sinter a powdered material of the substrate; a mask for receiving the optical signal generated by the diode array, the mask forming a liquid crystal polarization rotator, the liquid crystal polarization rotator including a liquid crystal module and a polarizer, wherein the liquid crystal module operates to receive and to rotate a first portion of the optical signal passing therethrough while allowing a second portion of the optical signal to pass therethrough without being rotated, and wherein the polarizer, which comprises a polarizing mirror, operates to reject by reflecting one of the first or second portions of the optical signal received from the liquid crystal module, and thus to prevent the one of the first or second portions from reaching the substrate, while the polarizer allows the other one of the first or second portions of the optical signal to reach the substrate, the liquid crystal module of the mask having a plurality of pixels arranged in a two dimensional pattern that are individually controlled to enable the mask to mask off one or more selected areas of a specific layer of the powdered material of the substrate, and wherein the mask absorbs substantially no optical energy from the optical signal; and at least one processor controlling an output of the diode array and assisting in controlling operation of the mask such that only selected one of the pixels are controlled to enable portions of the optical signal passing through the liquid crystal polarization rotator to be rotated to thus form the first portion of the optical signal; and wherein the diode array is configured to provide a power density of at least about 10kW/cm 2 at a two percent duty cycle.