In one example, a device for printing a three-dimensional object is described. The device may include at least one material application unit to deposit at least one material for a voxel of the three-dimensional object, a vertical cavity surface emitting laser array comprising a plurality of vertical cavity surface emitting lasers, the plurality of vertical cavity surface emitting lasers including a first vertical cavity surface emitting laser to operate at a first wavelength and a second vertical cavity surface emitting laser to operate at a second wavelength, and a processor to control a deposition of the at least one material for the voxel via the at least one material application unit and to control an application of electromagnetic energy via at least one of the plurality of vertical cavity surface emitting lasers to the voxel to alter at least one property of the at least one material.