Abstract: A method and apparatus for the treatment of a particular volume of material, plant or animal tissue including the steps of treating the material plant or animal tissue with at least one photo-active agent, wherein the particular volume of the material, plant or animal tissue retains at least a portion of the at least one photo-active agent, and then treating the particular volume of the material plant or animal tissue with light sufficient to promote a multi-photon excitation of at least one of the at least one photo-active agent retained in the particular volume of the material, plant or animal tissue, wherein the at least one photo-active agent becomes active in the particular volume of the material, plant or animal tissue.

Abstract: A method for the imaging of a particular volume of plant or animal tissue, wherein the plant or animal tissue contains at least one photo-active molecular agent. The method comprises the steps of treating the particular volume of the plant or animal tissue with light sufficient to promote a simultaneous two-photon excitation of the photo-active molecular agent contained in the particular volume of the plant or animal tissue, photo-activating at least one of the at least one photo-active molecular agent in the particular volume of the plant or animal tissue, thereby producing at least one photo-activated molecular agent, wherein the at least one photo-activated molecular agent emits energy, detecting the energy emitted by the at least one photo-activated molecular agent, and producing a detected energy signal which is characteristic of the particular volume of plant or animal tissue.