Towards intrinsic optical bistability of rare earth ion pairs in solids

A mechanism for intrinsic optical bistability (IOB) is presented for atomic systems which can be decomposed into two weakly interacting subsystems. It is shown that optical bistability should occur when the interaction between the two subsystems fluctuates more rapidly than the characteristic time of the interaction. This approach provides a semi-quantitative explanation of IOB for asymmetric ytterbium pairs in CsCdBr3 matrix.