The color of shock waves in photonic crystals

Unexpected and novel new physical phenomena result when light interacts with a shock wave or shock-like dielectric modulation propagating through a photonic crystal, or material with a periodic modulation of the index of refraction. These theoretically predicted new phenomena include the capture of light at the shock wave front and re-emission at a tunable pulse rate and carrier frequency across the photornc crystal bandgap, and bandwidth narrowing as opposed to the ubiquitous bandwidth broadening. To our knowledge, these effects do not occur in any other physical system. Reversed Doppler shifts are also predicted to be observable. Reversed Doppler shifts have never been observed in any system and have only been speculated to occur in pathological systems with simultaneously negative effective permittivity and permeability. The generality of these effects make them amenable to observation in a variety of time-dependent photonic crystal systems, which may have significant technological implications.