Phase contrast image microscopy using optical phase conjugation in a

Abstract

A method for producing an intensity contrast image from phase detail in a transparent phase object also removes spurious background artifacts and speckle from the light source resulting in clearer images. A laser beam or other coherent light source is directed through the transparent phase object and focused into a photorefractive hologram recording crystal where a temporary volume phase hologram is formed. Once the hologram has formed a phase conjugate beam is created and passes back through the transparent phase object and is directed to an apparatus which records an intensity background pattern consisting of coherent artifacts. The transparent phase object is then mechanically shifted or allowed to move on its own in the case of transparent living specimens. The light source is directed through the physically translated transparent phase object and focused into the photorefractive hologram recording crystal. Another phase conjugate beam, of the original unshifted phase object, is created and passes back through the physically translated transparent phase object and is directed to the apparatus which records the intensity image due to the phase conjugate of the original optical field passing through the physically translated phase object. The intensity pattern containing the background coherent artifacts is then subtracted from this intensity image which also contains the same background artifacts, resulting in an intensity image of the transparent phase object without coherent artifacts.