There is one unique solution to the logic part of the puzzle:
. . \ . . .
/ . \ . . .
. . . . . .
. \ . . . .
. . . . / .
. . . . . .
Extraction uses the additive properties of light. drawing out each beam of light,and adding the colors of beams that intersect, (like R + B = M) the colors of each square should be:
W C \ G Y G W White . Black
/ M \ C W C C Cyan R Red
R B R . R . Y Yellow G Green
Y \ M B M B M Magenta B Blue
R Y R R / M \/ Mirrors
R Y R . M .
Note that the letters also are in one of the WCYMRGB colors. The letters that would be visible in the colored grid are the green D, the red R, the magenta A, the magenta G, the yellow O, and the blue N.