A method for modifying the refractive index of an optical polymeric material. The method comprises continuously irradiating predetermined regions of an optical, polymeric material with femtosecond laser pulses to form a gradient index refractive structure within the material. The optical polymeric material can include a photosensitizer to increase the photoefficiency of the two-photo process resulting in the formation of the observed refractive structures. An optical device includes an optical, polymeric lens material having an anterior surface and posterior surface and an optical axis intersecting the surfaces and at least one laser-modified, GRIN layer disposed between the anterior surface and the posterior surface and arranged along a first axis 45° to 90° to the optical axis. The at least one laser-modified GRIN layer comprises a plurality of adjacent refractive segments characterized by a variation in index of refraction across at least one of at least a portion of the adjacent segments and along each segment.
