On Efficient Field Energy Conversion in Non-Phase-Matched Frequency Doubling Process

In the paper the efficiency of the light energy conversion from the fundamental wave into its second harmonics is analysed. A standard model of three waves mixing in media without centre of symmetry was applied. It was shown that the full conversion of energy is possible if an appropriate phase difference exists and provided that at least a minimal energy of the second wave is present on the input. The results are expressed both by analytical formulas and a phase space reconstruction. A simple experimental setup to enhance the second harmonics is proposed.