Degenerate Optical Parametric Amplification With Focused Gaussian Beams

We present the results of an accurate numerical model for degenerate optical parametric amplification with focused Gaussian beams. This model shows that the optimum phase difference between the pump and the signal beams can be significantly different from that predicted by the plane-wave theory, and that squeezing in excess of 10 dB can be obtained for relatively long interaction lengths and low pump power levels.