We show that nonlinear optical structures involving a balanced gain-loss profile can act as unidirectional optical valves. This is made possible by exploiting the interplay between the fundamental symmetries of parity (P) and time (T), with optical nonlinear effects. This unidirectional dynamics is specifically demonstrated for the case of an integrable PT-symmetric nonlinear system.
Ramezani, H. and Kottos, Tsampikos, "Unidirectional nonlinear PT -symmetric optical structures" (2010). Physics and Astronomy Faculty Publications and Presentations. 310.
Physical Review A