Thus, the photons from the combined image will be forced away from 
    that original focus, so as to produce an image elsewhere on the output 
    square. If the fringe component separating mask, located at the  
    holograms' common focus consists of a little round hole, then light
    from EITHER hologram will output through the hole. However, if both
    holograms are lit, destructive interference will take place at that
    hole, preventing any light from exiting the hole. 
 
      The photonic transistor product is, therefore, a NOT circuit...
    if one of the beams is left on all the time. In fact, the designer has a 
    choice of output light wave phases (not information phases) by 
    simply choosing which side will be left on. 
 
       To create an output image 180 degrees out of phase, we must change 
    the input wave front pixels by 180 degrees. Simply put, we change the 
    real number sign of each pixel using a program called NEGIMAGE.COM. 
 
      The syntax is NEGIMAGE IMAGE3.  We could designate a different filename 
    for the output, but since we have no further use of the present IMAGE3 
    file after it has served as our input, why waste disk space.