A new scheme for nondestructive characterization of quasi-phase-matching grating structures and temperature gradients through inverse Fourier theory using second-harmonic-generation experiments is proposed. By inserting a mirror to reflect the signals back through the sample, we show how it is possible to retrieve the relevant information by measuring only the generated second-harmonic power, avoiding more complicated phase measurements. The potential of the scheme is emphasized through theoretical and numerical investigations in the case of periodically poled lithium niobate bulk crystals.
Optical Society of America. Journal B: Optical Physics, 2004, Vol 21, Issue 6, p. 1137-1145