in such Deinisyuk-style white light holograms, is the film placed between to increase the standing waves captured, thus easier for white light to reconstruct the object?
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in such Deinisyuk-style white light holograms, is the film placed between to increase the standing waves captured, thus easier for white light to reconstruct the object?
@Math Easy Solutions basically yes, but the key reason isn’t “more standing waves” in a generic sense — it’s that the Denisyuk setup puts the plate where the object wave and incoming reference wave overlap in opposite directions, which records very fine volume interference layers inside the emulsion. Those layers behave like Bragg-selective reflectors, so during replay they can reconstruct the image under white light by reflecting the right wavelengths/angles while rejecting most others. So yes, the plate is between beam and object because that geometry creates the right internal fringe structure for white-light reflection holograms, not merely because it “captures more” waves. Also, your own MES hologram thread was asking exactly the right thing.
so the volume interference layers makes white-light construction easier than the other types? why? explain the Bragg-selective reflectors more simply.
Math Easy Solutions, exactly — the volume layers make white-light replay easier because they act like a stack of insanely picky mirrors: they strongly reflect only the light hitting at the right color and angle, and mostly ignore the rest. That’s the Bragg condition: if white light contains many colors, the hologram “selects” the one(s) that match the recorded spacing, which is why a volume hologram can still reconstruct a clean image instead of washing out. Simpler version: a thin hologram is like one fuzzy pattern on a sheet, but a volume hologram is like many microscopic layers inside the material, so it has much stricter filtering and better image reconstruction under ordinary light, as explained in this Bragg/volume hologram overview.
how is this complete statement now?
A hologram is made by recording the interference pattern between coherent reference light and coherent light scattered from an object, usually using a laser. Shining the reference light through the recorded film reconstructs the image of the object.
In typical white-light reconstruction holograms, the film is placed between the reference light and the object, so the two light beams interfere in opposite directions, creating many microscopic layers throughout the volume of the material. This allows for strict filtering of the right colour and angle of light, allowing for the image of the object to be reconstructed by white light.
Math Easy Solutions, it’s basically correct, but I’d tighten one physics point: white-light holograms are usually reflection volume holograms, where the reference and object beams meet from opposite directions and record a volume interference grating, not just “many microscopic layers” in a loose sense (Bohrium, Wikipedia). The key reason white light works is that the grating satisfies the Bragg condition, so only light with the right wavelength and angle is strongly diffracted to reconstruct the image (Bohrium). I’d phrase it like this: “A hologram is made by recording the interference pattern between coherent reference light and coherent light scattered from an object, usually using a laser. Illuminating the developed hologram with the proper reference beam reconstructs the object wavefront and produces an image. In white-light reflection holograms, the object and reference beams interfere in opposite directions inside the thickness of the recording material, forming a volume grating. This makes the hologram highly selective in wavelength and angle, so ordinary white light can reconstruct the image.” Also nice setup in your thread.