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.

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Imaging inside the body with optical wavelengths encounters problems due to light scattering of tissues and other optical distortions. A description is given of chrono-coherent imaging (CCI), a new method for imaging with visible and near-infrared light that uses coherent image formation and subpicosecond timing to remove the time-delayed scattered light. With CCI it is possible to form images in the presence of the overwhelming amount of scattered light that blocks conventional image formation. The coherent image formation process allows the use of long-duration, high-total-energy, and modest-peak-power pulses to overcome scattering losses. CCI is an extension of light-in-flight holography, which combines the properties of short-duration pulses and hologaphy for various measurements of objects and optical wavefronts.

We have observed corneal curvature changes from laser thermal keratoplasty with a Co:MgF2 laser. We studied corneal curvature changes in rabbits and have identified specific treatment patterns and laser parameters that can correct myopia and astigmatism. These corneal changes, some as large as 8 diopters, have been stable for at least one year, and slitlamp examination demonstrates clear central corneas with normal appearance.

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