A METHOD FOR THE EVALUATION OF THE GRATING ENVELOPE IN VOLUME HOLOGRAPHIC MEDIA

A novel method for measuring the three-dimensional spatial distributio n of gratings in a volume holographic medium is described. In this met hod, the diffraction of a uniform probe light wave is measured as a fu nction of the deviation (either in angle or wavelength). from the Brag g condition. The envelope function of the grating is obtained by solvi ng the coupled wave equations inversely. Not only the amplitude but al so the phase of the envelope function is obtained. This method allows for the depletion of the probe light wave in the hologram and is appli cable to both dielectric (refractive index) and absorption gratings. T he resolution and the maximum measurable depth in this method are disc ussed.