Broadband time-reversal of optical pulses using a switchable   photonic-crystal mirror
  Recently, Chumak et al. have demonstrated experimentally the time-reversal of microwave spin pulses based on non-adiabatically tuning the wave speed in a spatially-periodic manner. Here, we solve the associated wave equations analytically, and give an explicit formula for the reversal efficiency. We then discuss the implementation for short optical electromagnetic pulses and show that the new scheme may lead to their accurate time-reversal with efficiency higher than before. 
Yonatan Sivan and John B. Pendry
physics.optics