Investigation of the phase of the second-order susceptibility measured in off-resonant surface second-harmonic generation

Relative measurement of the phase of the surface second-order susceptibility is shown to be easily obtained in a surface second-harmonic generation experiment by inserting a quarter-wave plate on the fundamental and measuring the second-harmonic intensity vs. the fundamental ellipticity. This technique is applied to two samples: an isotropic surface of chiral molecules and a calcite crystal. In both cases, a dephasing between the different susceptibility components is observed.