The invention provides an apparatus for electromagnetically affecting a
particle of interest in a specimen. The apparatus includes (a) a stage
capable of supporting the specimen; (b) a detector including at least one
camera, wherein the detector is capable of resolving a particle of
interest within the specimen; (c) a means for locating the particle of
interest in three dimensions; (d) a means for focusing electromagnetic
radiation to a focal volume within the specimen; and (e) a means for
adjusting the relative positions of the stage and electromagnetic
radiation focusing means, thereby positioning the particle of interest
within the focal volume.