Photon propagation in a discrete fiber network: An interplay of   coherence and losses
  We study light propagation in a photonic system that shows stepwise evolution in a discretized environment. It resembles a discrete-time version of photonic waveguide arrays or quantum walks. By introducing controlled photon losses to our experimental setup, we observe unexpected effects like sub-exponential energy decay and formation of complex fractal patterns. This demonstrates that the interplay of linear losses, discreteness and energy gradients leads to genuinely new coherent phenomena in classical and quantum optical experiments. Moreover, the influence of decoherence is investigated. 
Alois Regensburger, Christoph Bersch, Benjamin Hinrichs, Georgy   Onishchukov, Andreas Schreiber, Christine Silberhorn, and ...
physics.optics quant-ph