Synthetic modal interferometric laser imaging.

Objects can be imaged if passed through a field formed by the interference of a Hermite-Gaussian (modal) laser beam with a spatial offset reference beam. The light intensity scattered by the object is electronically detected and spatially recorded onto film moving synchronously with the object. The recording is a hologram. In the reconstruction of the hologram, each object point produces a modal beam, and this collection of modal beams is matched filtered to yield an image characterized by a point spread function of Laguerre- Gaussian form. The resolution is dependent upon the waist size and order of the modal beam and is invariant with respect to object/source/detector distances. Theoretical and experimental results are given.