A flat object surface and a hologram plate are both illuminated at an oblique angle by laser light of short pulse duration or short coherence length. Only those parts of the object surface are holographically recorded that correspond to a small-pathlength difference between object beam and reference beam. The holographic plate therefore corresponds to an infinite set of gated viewing systems triggered by the traversing reference beam. Scanning along the processed plate produces a continuous-motion picture of the light in flight. This new technique probably represents the ultimate in high-speed photographic recording, as no mechanical or electrical inertia is involved.

Holographic recordings have been made using lasers of short coherence and pulse length. Continuous frameless moving pictures show the wave front (pulse front) of light reflected by a mirror and focused by a lens. Light passing through interferometers has also been studied using this new method of dynamic observation. Cross sections between a thin sheet of light and a 3-D object have been recorded to demonstrate the possibilities of contouring. Finally a number of future experiments are proposed ranging from the measurements of industrial products to the study of relativistic effects.

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We describe a new method for imaging with visible and near visible light inside media, such as tissues, which have strong light scattering. The chrono-coherent imaging (CCI) method is demonstrated in this paper for a transmission geometry where an absorbing object is completely hidden from normal visual observation by light scattering of the media. The resultant images are most similar to X rays, with cumulative transmission showing absorption features and refractive index differences in the media. We discuss laser coherence properties, coherence measurements, the relation of CCI to light-inflight holography, holographic film properties relevant to CCI, a particular optical setup for CCI, the results of a demonstration experiment imaging an absorbing object hidden by light scattering, and an experiment to estimate the clinical applicability of CCI.

We have succeeded we believe for the first time, in making a light-in-flight (LIF) recording using one single pulse of a mode-locked frequency doubled Nd:YAG laser. Many experiments made earlier with multiple picosecond pulses have been repeated and the results were the same. New experiments have become possible such as the contouring of a fast moving object and recording through a nonrigid scattering medium. We demonstrate a LIF transmission method for rejecting scattered light which can be developed into a method for diagnostic imaging inside living tissue.