Abstract

With ordinary holography the referencebeam intensity is typically about half of the output of the laser. This overwhelms low-intensity object fields, which, therefore, are not recorded on the hologram (e.g., low-level scattered light from the object of interest). The reason for this behavior is the in-line noise of the reference beam. One method for removing this noise is to reduce the reference beam illumination to the same intensity as the low-component object field. The experimental results of this approach show a noise-reduced hologram of high contrast. Furthermore, illuminating this hologram with a more powerful reference beam reconstructs an amplified image of the object field with reduced noise. We demonstrate this effect by observation of scratch patterns on glass with a field intensity of 0.01 µW/cm².

© 1990 Optical Society of America