Abstract: Apparatus for additive manufacturing includes a light source that emits light into an optical path that extends to a powder bed or other platform for additive manufacturing. A phase modulator in the optical path is controlled to present a 2D pattern of phase shifts that steer the light to provide a desired pattern of optical power density on the powder bed. In some embodiments the optical path includes elements that focus the light into a small spot on the powder bed and a scanner operative to scan the spot over the powder bed. In some embodiments the light from the optical path is distributed over an area of the powder bed. A pattern of optical power density within the spot or area may be altered by changing the data controlling the phase modulator.