Holographic endoscopy with gradient-index optical imaging systems and optical fibers

Single or assembled gradient-index (GRIN) rod lenses as endoscopic optical devices combined with optical fibers or articulating optical arms for flexible illuminating object beam and reference beam guidance provide the possibility of constructing an easy-to-handle holographic endoscopic arrangement for practical use in industry and medicine. Using the same GRIN optical device for both endoscopic imaging as well as illumination simultaneously, an enlargement of the limiting aperture for speckle noise reduction can be gained within the given outer diameter of the instrument compared with endoscopic systems with separate fiber bundle illumination. Reflections, which destroy the image information, can be suppressed by holographic subtraction.