US Patent 7790353 Multidirectional photoreactive absorption method

A method for enhancing photoreactive absorption in a specified volume element of a photoreactive composition. In one embodiment, the method includes: providing a photoreactive composition: providing a source of light (preferably, a pulsed laser) sufficient for simultaneous absorption of at least two photons by the photoreactive composition, the light source having a beam capable of being divided: dividing the light beam into a plurality of equal path length exposure beams: and focusing the exposure beams in a substantially non-counter propagating manner at a single volume element of the photoreactive composition simultaneously to react at least a portion of the photoreactive composition. In another embodiment, a method includes: providing a photoreactive composition capable of photoreactive absorption: and exposing the photoreactive composition to laser light from a plurality of substantially non-counter propagating directions simultaneously, wherein the light overlaps in time and space at a predetermined focus spot.