White-light gated holography in LiNbO₃

Abstract

Incoherent white light sources such as tungsten or xenon lamps is shown to provide cheap and convenient gating light for two-color hologram writing in Pr-doped LiNbO3 with much higher sensitivity than 514 nm Ar laser gating. Diffraction efficiency was found to be linear in gating intensity in the region of several watts/cm2 and sublinear above this. Plane wave gratings were written with two equal 676 nm beams. Sensitivity measurements as a function of wavelength showed that this improvement is due to the short wavelength components of the gating light. Some spatial variations of sensitivity on the scale of millimeters and of a factor of two in magnitude are noted. Two-color holograms were also written using Cr-on-glass data masks of 64 K pixels.