Two or more diodes using optical fibers

Vidar Hegdal

Friends, I just canít see how it would benefit to use two or more diode pointers, even if the beams are guided into the same optical fiber as described in the last Holotalk show. Using two pointers to produce a single beam hologram this way would, as I see it, produce two almost identical images in the film, but the two beams would not interfere with each other so that the exposure time canít be reduced. Instead the film will be overloaded with two almost identical images, in addition to the fog produced by the two beams that does not contribute to any interference pattern. Adding additional beams from even more pointers would just increase the fog level and crowd the film until you canít see any image at all. Using more than one pointer for producing a single beam hologram would therefore reduce the image quality. As you add more pointers, the exposure time will look like it has to be reduced, since the film now will go more rapidly black in the developer unless you reduce the exposure time. However, the apparent increase in power will just add noise to the image. Even if the pointers had exactly the same frequency (very unlikely), it would still not be possible to benefit from this multi-diode configuration since each unit would be at different places within their own bandwidth. (for the same reasons it is impossible to use two HeNe lasers for the same purpose) The proposed method would not be usable before we see laser diodes with bandwidths equal to zero and 100% equal frequencies.. Best regards, Vidar