One is that the phase difference tends to show sinusoidal variations as a function of the angle γB between the ambient magnetic field projected on the spin plane and the
In nonlinear crystals, the pump, signal and idler lights are overlapped, and the interaction between them leads to the corresponding gain obtained by the signal and idler light. The physical processes of DFG and OPA are basically the same and both require two beams of light (pump and signal ...