An apparatus (10; 100; 100') for performing an additive manufacturing operation to form a structure by processing a photopolymer resist material (48; 132), the apparatus (10; 100; 100') comprising: a motion stage (50; 130) configured to support and move the photopolymer resist material (48; 132) relative to a focused image plane; a laser source (12; 102) for generating a laser beam (25; 102'); a tunable mask (26; 110; 110') for receiving the laser beam (25; 102'), wherein the tunable mask (26; 110; 110') comprises an optically dispersive element; a control unit (27; 112; 140') to tune the tunable mask (26; 110; 110') to generate a plurality of differing images; the control unit (27; 112; 140') tuning the tunable mask (26; 110; 110') to split the laser beam (25; 102') into a plurality of emergent beams, wherein each said emergent beam emerging from the tunable mask (26; 110; 110') comprises a subplurality of beamlets of varying or identical intensity, for each one of the differing images, and wherein each said beamlet emerges from a unique subsection of illuminated regions of the tunable mask (26; 110; 110') during projection of each said differing image; a collimator (30; 114, 115; 115') for collecting and collimating at least one of the emergent beams from each said differing image, from the tunable mask (26; 110; 110') to form a collimated beam; the control unit (27; 112; 140') tuning the tunable mask (26; 110; 110') upon receiving a signal from the motion stage (50; 130); one or more focusing elements (42; 44; 128') to focus the collimated beam into a focused beam which is projected as the focused image plane on or within the photopolymer resist material (48; 132), wherein the tunable mask (26; 110; 110'), the collimator (30; 114, 115; 115'), and the focusing elements (42; 44; 128') are so oriented and positioned as to create the same optical path length between the tunable mask (26; 110; 110') and the focused image plane for all optical frequencies of the laser beam; and wherein the focused beam simultaneously illuminates a layer of the photopolymer resist material (48; 132), the control unit (27; 112; 140') tuning the tunable mask (26; 110; 110') such that the focused beam using the differing images generates a cumulative nonlinear exposure dose within the focused image plane to selectively polymerize portions of the photopolymer resist material (48; 132) within the focused image plane. a motion stage (50; 130) configured to support and move the photopolymer resist material (48; 132) relative to a focused image plane; a laser source (12; 102) for generating a laser beam (25; 102'); a tunable mask (26; 110; 110') for receiving the laser beam (25; 102'), wherein the tunable mask (26; 110; 110') comprises an optically dispersive element; a control unit (27; 112; 140') to tune the tunable mask (26; 110; 110') to generate a plurality of differing images; the control unit (27; 112; 140') tuning the tunable mask (26; 110; 110') to split the laser beam (25; 102') into a plurality of emergent beams, wherein each said emergent beam emerging from the tunable mask (26; 110; 110') comprises a subplurality of beamlets of varying or identical intensity, for each one of the differing images, and wherein each said beamlet emerges from a unique subsection of illuminated regions of the tunable mask (26; 110; 110') during projection of each said differing image; a collimator (30; 114, 115; 115') for collecting and collimating at least one of the emergent beams from each said differing image, from the tunable mask (26; 110; 110') to form a collimated beam; the control unit (27; 112; 140') tuning the tunable mask (26; 110; 110') upon receiving a signal from the motion stage (50; 130); one or more focusing elements (42; 44; 128') to focus the collimated beam into a focused beam which is projected as the focused image plane on or within the photopolymer resist material (48; 132), wherein the tunable mask (26; 110; 110'), the collimator (30; 114, 115; 115'), and the focusing elements (42; 44; 128') are so oriented and positioned as to create the same optical path length between the tunable mask (26; 110; 110') and the focused image plane for all optical frequencies of the laser beam; and wherein the focused beam simultaneously illuminates a layer of the photopolymer resist material (48; 132), the control unit (27; 112; 140') tuning the tunable mask (26; 110; 110') such that the focused beam using the differing images generates a cumulative nonlinear exposure dose within the focused image plane to selectively polymerize portions of the photopolymer resist material (48; 132) within the focused image plane.