Transmission Hologram Mechanics

Transmission holograms are characterized by their optical illumination pathway: the reconstruction light source is positioned behind the holographic medium, passing directly through it toward the observer. Pioneered by Leith and Upatnieks in 1962, this method played a critical role in the rise of optical holography.

Because the reconstructing light passes clean through the fine micro-grating, transmission setups do not rely on local color filtering within the film itself. This results in incredibly bright, sharp, and deep volumetric images. However, to maintain absolute focus and resolution, they typically require highly coherent monochrometer laser sources.

If illuminated using broad-spectrum white light, transmission plates disperse the rays like a prism, creating a blurry rainbow-colored smear. This spectral dispersion limitation ultimately inspired the development of complex slit-diffraction structures, leading to white-light viewable rainbow holograms.