Theory of wave-front reversal of short pulses in dynamically-tuned   zero-gap periodic systems
  Recently, we have shown that the wave-front of short pulses can be accurately and efficiently reversed by use of simple one-dimensional zero-gap photonic crystals. In this Article, we describe the analytical approach in detail, and discuss specific structures and modulation techniques as well as the required steps for achieving complete time-reversal. We also show that our scheme is only very weakly sensitive to material losses and dispersion. 
Yonatan Sivan, John B. Pendry
physics.optics