Systems, methods, and apparatus for photonic crystals logic devices are disclosed. In one or more embodiments, a disclosed method for an optical logic device comprises radiating, by at least one source, at least one signal. The method further comprises reflecting at least one signal off of at least one photonic crystal, when at least one photonic crystal senses a physical phenomena of a threshold strength. Also, the method comprises not reflecting at least one signal off of at least one photonic crystal, when at least one photonic crystal does not sense the physical phenomena of the threshold strength. Further, the method comprises detecting or not detecting, by at least one detector, at least one signal.